21157712377 has 8 divisors (see below), whose sum is σ = 21389276480. Its totient is φ = 20926829520.

The previous prime is 21157712369. The next prime is 21157712441. The reversal of 21157712377 is 77321775112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21157712377 - 2³ = 21157712369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21157713377) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 107733 + ... + 232210.

It is an arithmetic number, because the mean of its divisors is an integer number (2673659560).

Almost surely, 2^21157712377 is an apocalyptic number.

It is an amenable number.

21157712377 is a deficient number, since it is larger than the sum of its proper divisors (231564103).

21157712377 is a wasteful number, since it uses less digits than its factorization.

21157712377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 340623.

The product of its digits is 144060, while the sum is 43.

The spelling of 21157712377 in words is "twenty-one billion, one hundred fifty-seven million, seven hundred twelve thousand, three hundred seventy-seven".