78313131 has 24 divisors (see below), whose sum is σ = 122181696. Its totient is φ = 48049920.

The previous prime is 78313129. The next prime is 78313133. The reversal of 78313131 is 13131387.

It is an interprime number because it is at equal distance from previous prime (78313129) and next prime (78313133).

It is not a de Polignac number, because 78313131 - 2¹ = 78313129 is a prime.

It is a super-2 number, since 2×78313131² = 12265892974046322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78313095 and 78313104.

It is not an unprimeable number, because it can be changed into a prime (78313133) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 49651 + ... + 51203.

It is an arithmetic number, because the mean of its divisors is an integer number (5090904).

Almost surely, 2^78313131 is an apocalyptic number.

78313131 is a deficient number, since it is larger than the sum of its proper divisors (43868565).

78313131 is a wasteful number, since it uses less digits than its factorization.

78313131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2003 (or 2000 counting only the distinct ones).

The product of its digits is 1512, while the sum is 27.

The square root of 78313131 is about 8849.4706621357. The cubic root of 78313131 is about 427.8368577135.

It can be divided in two parts, 7 and 8313131, that added together give a palindrome (8313138).

The spelling of 78313131 in words is "seventy-eight million, three hundred thirteen thousand, one hundred thirty-one".