213121231020 has 144 divisors (see below), whose sum is σ = 670712410368. Its totient is φ = 54719562240.

The previous prime is 213121231003. The next prime is 213121231033. The reversal of 213121231020 is 20132121312.

213121231020 is a `hidden beast` number, since 21 + 312 + 1 + 2 + 310 + 20 = 666.

213121231020 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×213121231020² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 213121230984 and 213121231002.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1002322 + ... + 1196198.

It is an arithmetic number, because the mean of its divisors is an integer number (4657725072).

Almost surely, 2^213121231020 is an apocalyptic number.

213121231020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 213121231020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (335356205184).

213121231020 is an abundant number, since it is smaller than the sum of its proper divisors (457591179348).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

213121231020 is a wasteful number, since it uses less digits than its factorization.

213121231020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194120 (or 194115 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 213121231020 its reverse (20132121312), we get a palindrome (233253352332).

The spelling of 213121231020 in words is "two hundred thirteen billion, one hundred twenty-one million, two hundred thirty-one thousand, twenty".