21977923653 has 24 divisors (see below), whose sum is σ = 36343955648. Its totient is φ = 12537027072.

The previous prime is 21977923619. The next prime is 21977923661. The reversal of 21977923653 is 35632977912.

21977923653 is a `hidden beast` number, since 2 + 197 + 7 + 92 + 365 + 3 = 666.

It is not a de Polignac number, because 21977923653 - 2⁸ = 21977923397 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21977923653.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21977923853) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 265951 + ... + 338652.

Almost surely, 2^21977923653 is an apocalyptic number.

It is an amenable number.

21977923653 is a deficient number, since it is larger than the sum of its proper divisors (14366031995).

21977923653 is a wasteful number, since it uses less digits than its factorization.

21977923653 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 605193 (or 605190 counting only the distinct ones).

The product of its digits is 4286520, while the sum is 54.

The spelling of 21977923653 in words is "twenty-one billion, nine hundred seventy-seven million, nine hundred twenty-three thousand, six hundred fifty-three".