21557157715641 has 24 divisors (see below), whose sum is σ = 30090386363296. Its totient is φ = 13726698860160.

The previous prime is 21557157715633. The next prime is 21557157715673. The reversal of 21557157715641 is 14651775175512.

It is not a de Polignac number, because 21557157715641 - 2³ = 21557157715633 is a prime.

It is a super-2 number, since 2×21557157715641² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21557157715601) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8732320 + ... + 10925553.

Almost surely, 2^{21557157715641} is an apocalyptic number.

It is an amenable number.

21557157715641 is a deficient number, since it is larger than the sum of its proper divisors (8533228647655).

21557157715641 is a wasteful number, since it uses less digits than its factorization.

21557157715641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19658613 (or 19658590 counting only the distinct ones).

The product of its digits is 10290000, while the sum is 57.

The spelling of 21557157715641 in words is "twenty-one trillion, five hundred fifty-seven billion, one hundred fifty-seven million, seven hundred fifteen thousand, six hundred forty-one".