21766077621 has 16 divisors (see below), whose sum is σ = 32426193600. Its totient is φ = 14429649744.

The previous prime is 21766077601. The next prime is 21766077643. The reversal of 21766077621 is 12677066712.

21766077621 is a `hidden beast` number, since 2 + 17 + 6 + 6 + 0 + 7 + 7 + 621 = 666.

It is not a de Polignac number, because 21766077621 - 2²² = 21761883317 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21766077601) 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, 2246986 + ... + 2256651.

It is an arithmetic number, because the mean of its divisors is an integer number (2026637100).

Almost surely, 2^21766077621 is an apocalyptic number.

It is an amenable number.

21766077621 is a deficient number, since it is larger than the sum of its proper divisors (10660115979).

21766077621 is a wasteful number, since it uses less digits than its factorization.

21766077621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4503825 (or 4503819 counting only the distinct ones).

The product of its (nonzero) digits is 296352, while the sum is 45.

The spelling of 21766077621 in words is "twenty-one billion, seven hundred sixty-six million, seventy-seven thousand, six hundred twenty-one".