78663631 has 4 divisors (see below), whose sum is σ = 81376200. Its totient is φ = 75951064.

The previous prime is 78663617. The next prime is 78663659. The reversal of 78663631 is 13636687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13636687 = 659 ⋅20693.

It is a cyclic number.

It is not a de Polignac number, because 78663631 - 2⁷ = 78663503 is a prime.

It is a super-2 number, since 2×78663631² = 12375933684208322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78663691) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1356241 + ... + 1356298.

It is an arithmetic number, because the mean of its divisors is an integer number (20344050).

Almost surely, 2^78663631 is an apocalyptic number.

78663631 is a deficient number, since it is larger than the sum of its proper divisors (2712569).

78663631 is a wasteful number, since it uses less digits than its factorization.

78663631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2712568.

The product of its digits is 108864, while the sum is 40.

The square root of 78663631 is about 8869.2519977730. The cubic root of 78663631 is about 428.4741865779.

The spelling of 78663631 in words is "seventy-eight million, six hundred sixty-three thousand, six hundred thirty-one".