68640631 has 2 divisors, whose sum is σ = 68640632. Its totient is φ = 68640630.

The previous prime is 68640623. The next prime is 68640647. The reversal of 68640631 is 13604686.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 68640631 - 2³ = 68640623 is a prime.

It is a super-2 number, since 2×68640631² = 9423072448156322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68640931) 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 as a sum of consecutive naturals, namely, 34320315 + 34320316.

It is an arithmetic number, because the mean of its divisors is an integer number (34320316).

Almost surely, 2^68640631 is an apocalyptic number.

68640631 is a deficient number, since it is larger than the sum of its proper divisors (1).

68640631 is an equidigital number, since it uses as much as digits as its factorization.

68640631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 68640631 is about 8284.9641520045. The cubic root of 68640631 is about 409.4432876469.

The spelling of 68640631 in words is "sixty-eight million, six hundred forty thousand, six hundred thirty-one".