78731 has 4 divisors (see below), whose sum is σ = 79464. Its totient is φ = 78000.

The previous prime is 78721. The next prime is 78737. The reversal of 78731 is 13787.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 13787 = 17 ⋅811.

It is a cyclic number.

It is not a de Polignac number, because 78731 - 2¹⁴ = 62347 is a prime.

It is a super-2 number, since 2×78731² = 12397140722, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 9 and base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 78731.

It is not an unprimeable number, because it can be changed into a prime (78737) 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, 170 + ... + 431.

It is an arithmetic number, because the mean of its divisors is an integer number (19866).

2⁷⁸⁷³¹ is an apocalyptic number.

78731 is a deficient number, since it is larger than the sum of its proper divisors (733).

78731 is a wasteful number, since it uses less digits than its factorization.

78731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 732.

The product of its digits is 1176, while the sum is 26.

The square root of 78731 is about 280.5904488752. The cubic root of 78731 is about 42.8596469436.

It can be divided in two parts, 787 and 31, that added together give a palindrome (818).

The spelling of 78731 in words is "seventy-eight thousand, seven hundred thirty-one".