21657156055 has 8 divisors (see below), whose sum is σ = 26084487744. Its totient is φ = 17261791200.

The previous prime is 21657156041. The next prime is 21657156067. The reversal of 21657156055 is 55065175612.

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

It is not a de Polignac number, because 21657156055 - 2¹¹ = 21657154007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7990216 + ... + 7992925.

It is an arithmetic number, because the mean of its divisors is an integer number (3260560968).

Almost surely, 2^21657156055 is an apocalyptic number.

21657156055 is a deficient number, since it is larger than the sum of its proper divisors (4427331689).

21657156055 is a wasteful number, since it uses less digits than its factorization.

21657156055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15983417.

The product of its (nonzero) digits is 315000, while the sum is 43.

The spelling of 21657156055 in words is "twenty-one billion, six hundred fifty-seven million, one hundred fifty-six thousand, fifty-five".