21969844551 has 6 divisors (see below), whose sum is σ = 31734219920. Its totient is φ = 14646563028.

The previous prime is 21969844493. The next prime is 21969844577. The reversal of 21969844551 is 15544896912.

21969844551 is a `hidden beast` number, since 2 + 1 + 9 + 6 + 9 + 84 + 4 + 551 = 666.

It is not a de Polignac number, because 21969844551 - 2⁶ = 21969844487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21969844051) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1220546911 + ... + 1220546928.

Almost surely, 2^21969844551 is an apocalyptic number.

21969844551 is a deficient number, since it is larger than the sum of its proper divisors (9764375369).

21969844551 is a wasteful number, since it uses less digits than its factorization.

21969844551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2441093845 (or 2441093842 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 54.

The spelling of 21969844551 in words is "twenty-one billion, nine hundred sixty-nine million, eight hundred forty-four thousand, five hundred fifty-one".