668181887 has 2 divisors, whose sum is σ = 668181888. Its totient is φ = 668181886.

The previous prime is 668181851. The next prime is 668181919. The reversal of 668181887 is 788181866.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 668181887 - 2²⁴ = 651404671 is a prime.

It is a super-2 number, since 2×668181887² = 892934068229761538, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668181817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334090943 + 334090944.

It is an arithmetic number, because the mean of its divisors is an integer number (334090944).

Almost surely, 2^668181887 is an apocalyptic number.

668181887 is a deficient number, since it is larger than the sum of its proper divisors (1).

668181887 is an equidigital number, since it uses as much as digits as its factorization.

668181887 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1032192, while the sum is 53.

The square root of 668181887 is about 25849.2144368064. The cubic root of 668181887 is about 874.2417973982.

The spelling of 668181887 in words is "six hundred sixty-eight million, one hundred eighty-one thousand, eight hundred eighty-seven".