21210202120 has 32 divisors (see below), whose sum is σ = 49368576600. Its totient is φ = 8191525888.

The previous prime is 21210202063. The next prime is 21210202141. The reversal of 21210202120 is 2120201212.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10815584004 + 10394618116 = 103998^2 + 101954^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21210202120.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9141169 + ... + 9143488.

Almost surely, 2^21210202120 is an apocalyptic number.

21210202120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210202120 is an abundant number, since it is smaller than the sum of its proper divisors (28158374480).

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

21210202120 is a wasteful number, since it uses less digits than its factorization.

21210202120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18284697 (or 18284693 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21210202120 its reverse (2120201212), we get a palindrome (23330403332).

The spelling of 21210202120 in words is "twenty-one billion, two hundred ten million, two hundred two thousand, one hundred twenty".