21157730115 has 32 divisors (see below), whose sum is σ = 34570229760. Its totient is φ = 11045813376.

The previous prime is 21157730063. The next prime is 21157730147. The reversal of 21157730115 is 51103775112.

It is not a de Polignac number, because 21157730115 - 2¹⁵ = 21157697347 is a prime.

It is a super-4 number, since 4×21157730115⁴ (a number of 42 digits) contains 4444 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 318694 + ... + 379316.

It is an arithmetic number, because the mean of its divisors is an integer number (1080319680).

Almost surely, 2^21157730115 is an apocalyptic number.

21157730115 is a deficient number, since it is larger than the sum of its proper divisors (13412499645).

21157730115 is a wasteful number, since it uses less digits than its factorization.

21157730115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61123.

The product of its (nonzero) digits is 7350, while the sum is 33.

The spelling of 21157730115 in words is "twenty-one billion, one hundred fifty-seven million, seven hundred thirty thousand, one hundred fifteen".