21200012120 has 64 divisors (see below), whose sum is σ = 55282176000. Its totient is φ = 7166194560.

The previous prime is 21200012107. The next prime is 21200012131. The reversal of 21200012120 is 2121000212.

It is a happy number.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 513320 + ... + 553079.

It is an arithmetic number, because the mean of its divisors is an integer number (863784000).

Almost surely, 2^21200012120 is an apocalyptic number.

21200012120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21200012120 is an abundant number, since it is smaller than the sum of its proper divisors (34082163880).

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

21200012120 is a wasteful number, since it uses less digits than its factorization.

21200012120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1066488 (or 1066484 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21200012120 its reverse (2121000212), we get a palindrome (23321012332).

The spelling of 21200012120 in words is "twenty-one billion, two hundred million, twelve thousand, one hundred twenty".