78289931 has 4 divisors (see below), whose sum is σ = 78385200. Its totient is φ = 78194664.

The previous prime is 78289927. The next prime is 78289933. The reversal of 78289931 is 13998287.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13998287 = 2741 ⋅5107.

It is a cyclic number.

It is not a de Polignac number, because 78289931 - 2² = 78289927 is a prime.

It is a super-2 number, since 2×78289931² = 12258626591969522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78289933) 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, 46391 + ... + 48048.

It is an arithmetic number, because the mean of its divisors is an integer number (19596300).

Almost surely, 2^78289931 is an apocalyptic number.

78289931 is a deficient number, since it is larger than the sum of its proper divisors (95269).

78289931 is an equidigital number, since it uses as much as digits as its factorization.

78289931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95268.

The product of its digits is 217728, while the sum is 47.

The square root of 78289931 is about 8848.1597521745. The cubic root of 78289931 is about 427.7946051338.

The spelling of 78289931 in words is "seventy-eight million, two hundred eighty-nine thousand, nine hundred thirty-one".