666138157 has 8 divisors (see below), whose sum is σ = 701503200. Its totient is φ = 630803664.

The previous prime is 666138133. The next prime is 666138173. The reversal of 666138157 is 751831666.

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

It is a cyclic number.

It is not a de Polignac number, because 666138157 - 2²³ = 657749549 is a prime.

It is a super-2 number, since 2×666138157² = 887480088422713298, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666138197) 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 7 ways as a sum of consecutive naturals, for example, 47343 + ... + 59779.

It is an arithmetic number, because the mean of its divisors is an integer number (87687900).

Almost surely, 2^666138157 is an apocalyptic number.

It is an amenable number.

666138157 is a deficient number, since it is larger than the sum of its proper divisors (35365043).

666138157 is a wasteful number, since it uses less digits than its factorization.

666138157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15275.

The product of its digits is 181440, while the sum is 43.

The square root of 666138157 is about 25809.6523998290. The cubic root of 666138157 is about 873.3495558466.

The spelling of 666138157 in words is "six hundred sixty-six million, one hundred thirty-eight thousand, one hundred fifty-seven".