21277765157 has 32 divisors (see below), whose sum is σ = 23781600000. Its totient is φ = 18876464640.

The previous prime is 21277765139. The next prime is 21277765177. The reversal of 21277765157 is 75156777212.

It is not a de Polignac number, because 21277765157 - 2⁸ = 21277764901 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 (21277765177) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 29027963 + ... + 29028695.

It is an arithmetic number, because the mean of its divisors is an integer number (743175000).

Almost surely, 2^21277765157 is an apocalyptic number.

It is an amenable number.

21277765157 is a deficient number, since it is larger than the sum of its proper divisors (2503834843).

21277765157 is a wasteful number, since it uses less digits than its factorization.

21277765157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1181.

The product of its digits is 1440600, while the sum is 50.

The spelling of 21277765157 in words is "twenty-one billion, two hundred seventy-seven million, seven hundred sixty-five thousand, one hundred fifty-seven".