21012210100 has 72 divisors (see below), whose sum is σ = 53219093760. Its totient is φ = 7050894720.

The previous prime is 21012210049. The next prime is 21012210113. The reversal of 21012210100 is 101221012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 286435 + ... + 352234.

It is an arithmetic number, because the mean of its divisors is an integer number (739154080).

Almost surely, 2^21012210100 is an apocalyptic number.

21012210100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012210100 is an abundant number, since it is smaller than the sum of its proper divisors (32206883660).

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

21012210100 is a wasteful number, since it uses less digits than its factorization.

21012210100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 638737 (or 638730 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21012210100 its reverse (101221012), we get a palindrome (21113431112).

The spelling of 21012210100 in words is "twenty-one billion, twelve million, two hundred ten thousand, one hundred".