78931631 has 2 divisors, whose sum is σ = 78931632. Its totient is φ = 78931630.

The previous prime is 78931613. The next prime is 78931667. The reversal of 78931631 is 13613987.

Together with previous prime (78931613) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is an emirp because it is prime and its reverse (13613987) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78931631 - 2¹⁴ = 78915247 is a prime.

It is a super-2 number, since 2×78931631² = 12460404744640322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78937631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39465815 + 39465816.

It is an arithmetic number, because the mean of its divisors is an integer number (39465816).

Almost surely, 2^78931631 is an apocalyptic number.

78931631 is a deficient number, since it is larger than the sum of its proper divisors (1).

78931631 is an equidigital number, since it uses as much as digits as its factorization.

78931631 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 38.

The square root of 78931631 is about 8884.3475280968. The cubic root of 78931631 is about 428.9602261889.

The spelling of 78931631 in words is "seventy-eight million, nine hundred thirty-one thousand, six hundred thirty-one".