167961991 has 2 divisors, whose sum is σ = 167961992. Its totient is φ = 167961990.

The previous prime is 167961961. The next prime is 167962007. The reversal of 167961991 is 199169761.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-167961991 is a prime.

It is a super-2 number, since 2×167961991² = 56422460841368162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (167961961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83980995 + 83980996.

It is an arithmetic number, because the mean of its divisors is an integer number (83980996).

Almost surely, 2^167961991 is an apocalyptic number.

167961991 is a deficient number, since it is larger than the sum of its proper divisors (1).

167961991 is an equidigital number, since it uses as much as digits as its factorization.

167961991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 183708, while the sum is 49.

The square root of 167961991 is about 12960.0150848678. The cubic root of 167961991 is about 551.7432194594.

The spelling of 167961991 in words is "one hundred sixty-seven million, nine hundred sixty-one thousand, nine hundred ninety-one".