21157635423 has 16 divisors (see below), whose sum is σ = 28478632160. Its totient is φ = 13970952576.

The previous prime is 21157635407. The next prime is 21157635427. The reversal of 21157635423 is 32453675112.

It is not a de Polignac number, because 21157635423 - 2⁴ = 21157635407 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 (21157635427) 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, 1140861 + ... + 1159257.

It is an arithmetic number, because the mean of its divisors is an integer number (1779914510).

Almost surely, 2^21157635423 is an apocalyptic number.

21157635423 is a deficient number, since it is larger than the sum of its proper divisors (7320996737).

21157635423 is a wasteful number, since it uses less digits than its factorization.

21157635423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22026.

The product of its digits is 151200, while the sum is 39.

The spelling of 21157635423 in words is "twenty-one billion, one hundred fifty-seven million, six hundred thirty-five thousand, four hundred twenty-three".