78917631 has 8 divisors (see below), whose sum is σ = 113317680. Its totient is φ = 48564672.

The previous prime is 78917627. The next prime is 78917647. The reversal of 78917631 is 13671987.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 78917631 - 2² = 78917627 is a prime.

It is a super-2 number, since 2×78917631² = 12455984965304322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78917611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1011726 + ... + 1011803.

It is an arithmetic number, because the mean of its divisors is an integer number (14164710).

Almost surely, 2^78917631 is an apocalyptic number.

78917631 is a deficient number, since it is larger than the sum of its proper divisors (34400049).

78917631 is a wasteful number, since it uses less digits than its factorization.

78917631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2023545.

The product of its digits is 63504, while the sum is 42.

The square root of 78917631 is about 8883.5595906146. The cubic root of 78917631 is about 428.9348633182.

The spelling of 78917631 in words is "seventy-eight million, nine hundred seventeen thousand, six hundred thirty-one".