21210131020 has 96 divisors (see below), whose sum is σ = 48730655232. Its totient is φ = 7707322368.

The previous prime is 21210130927. The next prime is 21210131051. The reversal of 21210131020 is 2013101212.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11633829 + ... + 11635651.

It is an arithmetic number, because the mean of its divisors is an integer number (507610992).

Almost surely, 2^21210131020 is an apocalyptic number.

21210131020 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 21210131020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24365327616).

21210131020 is an abundant number, since it is smaller than the sum of its proper divisors (27520524212).

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

21210131020 is a wasteful number, since it uses less digits than its factorization.

21210131020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2531 (or 2529 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21210131020 its reverse (2013101212), we get a palindrome (23223232232).

The spelling of 21210131020 in words is "twenty-one billion, two hundred ten million, one hundred thirty-one thousand, twenty".