21554656201 has 16 divisors (see below), whose sum is σ = 24587965584. Its totient is φ = 18718746624.

The previous prime is 21554656187. The next prime is 21554656213. The reversal of 21554656201 is 10265645512.

It can be written as a sum of positive squares in 8 ways, for example, as 2003905225 + 19550750976 = 44765^2 + 139824^2 .

It is a cyclic number.

It is not a de Polignac number, because 21554656201 - 2⁵ = 21554656169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21554656271) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 577045 + ... + 613261.

It is an arithmetic number, because the mean of its divisors is an integer number (1536747849).

Almost surely, 2^21554656201 is an apocalyptic number.

It is an amenable number.

21554656201 is a deficient number, since it is larger than the sum of its proper divisors (3033309383).

21554656201 is a wasteful number, since it uses less digits than its factorization.

21554656201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38940.

The product of its (nonzero) digits is 72000, while the sum is 37.

The spelling of 21554656201 in words is "twenty-one billion, five hundred fifty-four million, six hundred fifty-six thousand, two hundred one".