21021214956 has 48 divisors (see below), whose sum is σ = 56110145280. Its totient is φ = 6000321600.

The previous prime is 21021214939. The next prime is 21021214993. The reversal of 21021214956 is 65941212012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30771 + ... + 207338.

It is an arithmetic number, because the mean of its divisors is an integer number (1168961360).

Almost surely, 2^21021214956 is an apocalyptic number.

It is an amenable number.

21021214956 is an abundant number, since it is smaller than the sum of its proper divisors (35088930324).

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

21021214956 is a wasteful number, since it uses less digits than its factorization.

21021214956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239174 (or 239172 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 33.

Adding to 21021214956 its reverse (65941212012), we get a palindrome (86962426968).

The spelling of 21021214956 in words is "twenty-one billion, twenty-one million, two hundred fourteen thousand, nine hundred fifty-six".