21002220120 has 64 divisors (see below), whose sum is σ = 72007614720. Its totient is φ = 4800507264.

The previous prime is 21002220103. The next prime is 21002220139. The reversal of 21002220120 is 2102220012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21002220096 and 21002220105.

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 15 ways as a sum of consecutive naturals, for example, 12500482 + ... + 12502161.

It is an arithmetic number, because the mean of its divisors is an integer number (1125118980).

Almost surely, 2^21002220120 is an apocalyptic number.

21002220120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002220120 is an abundant number, since it is smaller than the sum of its proper divisors (51005394600).

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

21002220120 is a wasteful number, since it uses less digits than its factorization.

21002220120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25002664 (or 25002660 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21002220120 its reverse (2102220012), we get a palindrome (23104440132).

The spelling of 21002220120 in words is "twenty-one billion, two million, two hundred twenty thousand, one hundred twenty".