21010020120 has 96 divisors (see below), whose sum is σ = 68302634400. Its totient is φ = 5601025536.

The previous prime is 21010020113. The next prime is 21010020131. The reversal of 21010020120 is 2102001012.

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

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, 1678204 + ... + 1690676.

It is an arithmetic number, because the mean of its divisors is an integer number (711485775).

Almost surely, 2^21010020120 is an apocalyptic number.

21010020120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21010020120 is an abundant number, since it is smaller than the sum of its proper divisors (47292614280).

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

21010020120 is a wasteful number, since it uses less digits than its factorization.

21010020120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17169 (or 17162 counting only the distinct ones).

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

Adding to 21010020120 its reverse (2102001012), we get a palindrome (23112021132).

The spelling of 21010020120 in words is "twenty-one billion, ten million, twenty thousand, one hundred twenty".