221376521065 has 24 divisors (see below), whose sum is σ = 309059538120. Its totient is φ = 151783365888.

The previous prime is 221376521057. The next prime is 221376521077. The reversal of 221376521065 is 560125673122.

It can be written as a sum of positive squares in 4 ways, for example, as 24349729936 + 197026791129 = 156044^2 + 443877^2 .

It is not a de Polignac number, because 221376521065 - 2³ = 221376521057 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2263191 + ... + 2358979.

It is an arithmetic number, because the mean of its divisors is an integer number (12877480755).

Almost surely, 2^221376521065 is an apocalyptic number.

It is an amenable number.

221376521065 is a deficient number, since it is larger than the sum of its proper divisors (87683017055).

221376521065 is an equidigital number, since it uses as much as digits as its factorization.

221376521065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105241 (or 105234 counting only the distinct ones).

The product of its (nonzero) digits is 151200, while the sum is 40.

The spelling of 221376521065 in words is "two hundred twenty-one billion, three hundred seventy-six million, five hundred twenty-one thousand, sixty-five".