21556263162921 has 8 divisors (see below), whose sum is σ = 28759636556064. Its totient is φ = 14361865939200.

The previous prime is 21556263162899. The next prime is 21556263162943. The reversal of 21556263162921 is 12926136265512.

It is an interprime number because it is at equal distance from previous prime (21556263162899) and next prime (21556263162943).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21556263162921 - 2¹⁹ = 21556262638633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21556263169921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2244036751 + ... + 2244046356.

It is an arithmetic number, because the mean of its divisors is an integer number (3594954569508).

Almost surely, 2^{21556263162921} is an apocalyptic number.

It is an amenable number.

21556263162921 is a deficient number, since it is larger than the sum of its proper divisors (7203373393143).

21556263162921 is a wasteful number, since it uses less digits than its factorization.

21556263162921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4488084711.

The product of its digits is 2332800, while the sum is 51.

The spelling of 21556263162921 in words is "twenty-one trillion, five hundred fifty-six billion, two hundred sixty-three million, one hundred sixty-two thousand, nine hundred twenty-one".