157666509 has 144 divisors (see below), whose sum is σ = 323779456. Its totient is φ = 71850240.

The previous prime is 157666501. The next prime is 157666511. The reversal of 157666509 is 905666751.

It is not a de Polignac number, because 157666509 - 2³ = 157666501 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (157666501) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 3666642 + ... + 3666684.

Almost surely, 2^157666509 is an apocalyptic number.

It is an amenable number.

157666509 is an abundant number, since it is smaller than the sum of its proper divisors (166112947).

157666509 is a wasteful number, since it uses less digits than its factorization.

157666509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128 (or 114 counting only the distinct ones).

The product of its (nonzero) digits is 340200, while the sum is 45.

The square root of 157666509 is about 12556.5325229539. The cubic root of 157666509 is about 540.2313926025.

It can be divided in two parts, 157 and 666509, that added together give a palindrome (666666).

The spelling of 157666509 in words is "one hundred fifty-seven million, six hundred sixty-six thousand, five hundred nine".