20100021210 has 80 divisors (see below), whose sum is σ = 54200601576. Its totient is φ = 5344745472.

The previous prime is 20100021197. The next prime is 20100021217. The reversal of 20100021210 is 1212000102.

It can be written as a sum of positive squares in 4 ways, for example, as 17315664921 + 2784356289 = 131589^2 + 52767^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 20100021192 and 20100021201.

It is not an unprimeable number, because it can be changed into a prime (20100021217) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 250782 + ... + 321078.

Almost surely, 2^20100021210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20100021210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27100300788).

20100021210 is an abundant number, since it is smaller than the sum of its proper divisors (34100580366).

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

20100021210 is a wasteful number, since it uses less digits than its factorization.

20100021210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70669 (or 70660 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 20100021210 its reverse (1212000102), we get a palindrome (21312021312).

The spelling of 20100021210 in words is "twenty billion, one hundred million, twenty-one thousand, two hundred ten".