78181984 has 24 divisors (see below), whose sum is σ = 154730520. Its totient is φ = 38885376.

The previous prime is 78181981. The next prime is 78182003. The reversal of 78181984 is 48918187.

It is a super-2 number, since 2×78181984² = 12224845244352512, which contains 22 as substring.

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78181981) 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, 154 + ... + 12505.

It is an arithmetic number, because the mean of its divisors is an integer number (6447105).

Almost surely, 2^78181984 is an apocalyptic number.

It is an amenable number.

78181984 is a deficient number, since it is larger than the sum of its proper divisors (76548536).

78181984 is a wasteful number, since it uses less digits than its factorization.

78181984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12862 (or 12854 counting only the distinct ones).

The product of its digits is 129024, while the sum is 46.

The square root of 78181984 is about 8842.0576790700. The cubic root of 78181984 is about 427.5978987629.

The spelling of 78181984 in words is "seventy-eight million, one hundred eighty-one thousand, nine hundred eighty-four".