78239491 has 16 divisors (see below), whose sum is σ = 94307328. Its totient is φ = 64028800.

The previous prime is 78239479. The next prime is 78239503. The reversal of 78239491 is 19493287.

It is an interprime number because it is at equal distance from previous prime (78239479) and next prime (78239503).

It is not a de Polignac number, because 78239491 - 2⁵ = 78239459 is a prime.

It is a super-2 number, since 2×78239491² = 12242835903878162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78239401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4795 + ... + 13396.

It is an arithmetic number, because the mean of its divisors is an integer number (5894208).

Almost surely, 2^78239491 is an apocalyptic number.

78239491 is a deficient number, since it is larger than the sum of its proper divisors (16067837).

78239491 is a wasteful number, since it uses less digits than its factorization.

78239491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18242.

The product of its digits is 108864, while the sum is 43.

The square root of 78239491 is about 8845.3089827320. The cubic root of 78239491 is about 427.7027133869.

The spelling of 78239491 in words is "seventy-eight million, two hundred thirty-nine thousand, four hundred ninety-one".