667156631 has 2 divisors, whose sum is σ = 667156632. Its totient is φ = 667156630.

The previous prime is 667156621. The next prime is 667156639. The reversal of 667156631 is 136651766.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 667156631 - 2¹⁴ = 667140247 is a prime.

It is a super-2 number, since 2×667156631² = 890195940574540322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667156639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333578315 + 333578316.

It is an arithmetic number, because the mean of its divisors is an integer number (333578316).

Almost surely, 2^667156631 is an apocalyptic number.

667156631 is a deficient number, since it is larger than the sum of its proper divisors (1).

667156631 is an equidigital number, since it uses as much as digits as its factorization.

667156631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 136080, while the sum is 41.

The square root of 667156631 is about 25829.3753505577. The cubic root of 667156631 is about 873.7944239637.

The spelling of 667156631 in words is "six hundred sixty-seven million, one hundred fifty-six thousand, six hundred thirty-one".