157215665 has 4 divisors (see below), whose sum is σ = 188658804. Its totient is φ = 125772528.

The previous prime is 157215661. The next prime is 157215673. The reversal of 157215665 is 566512751.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 70576801 + 86638864 = 8401^2 + 9308^2 .

It is a cyclic number.

It is not a de Polignac number, because 157215665 - 2² = 157215661 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (157215661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15721562 + ... + 15721571.

It is an arithmetic number, because the mean of its divisors is an integer number (47164701).

Almost surely, 2^157215665 is an apocalyptic number.

It is an amenable number.

157215665 is a deficient number, since it is larger than the sum of its proper divisors (31443139).

157215665 is an equidigital number, since it uses as much as digits as its factorization.

157215665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31443138.

The product of its digits is 63000, while the sum is 38.

The square root of 157215665 is about 12538.5671031422. The cubic root of 157215665 is about 539.7159743216.

The spelling of 157215665 in words is "one hundred fifty-seven million, two hundred fifteen thousand, six hundred sixty-five".