21125621157 has 8 divisors (see below), whose sum is σ = 28168450176. Its totient is φ = 14083269792.

The previous prime is 21125621137. The next prime is 21125621189. The reversal of 21125621157 is 75112652112.

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

It is not a de Polignac number, because 21125621157 - 2⁶ = 21125621093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21125621107) 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, 1188 + ... + 205554.

It is an arithmetic number, because the mean of its divisors is an integer number (3521056272).

Almost surely, 2^21125621157 is an apocalyptic number.

It is an amenable number.

21125621157 is a deficient number, since it is larger than the sum of its proper divisors (7042829019).

21125621157 is a wasteful number, since it uses less digits than its factorization.

21125621157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238827.

The product of its digits is 8400, while the sum is 33.

The spelling of 21125621157 in words is "twenty-one billion, one hundred twenty-five million, six hundred twenty-one thousand, one hundred fifty-seven".