78390874 has 4 divisors (see below), whose sum is σ = 117586314. Its totient is φ = 39195436.

The previous prime is 78390853. The next prime is 78390883. The reversal of 78390874 is 47809387.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 70308225 + 8082649 = 8385^2 + 2843^2 .

It is a super-2 number, since 2×78390874² = 12290258252967752, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19597717 + ... + 19597720.

Almost surely, 2^78390874 is an apocalyptic number.

78390874 is a deficient number, since it is larger than the sum of its proper divisors (39195440).

78390874 is a wasteful number, since it uses less digits than its factorization.

78390874 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39195439.

The product of its (nonzero) digits is 338688, while the sum is 46.

The square root of 78390874 is about 8853.8620951537. The cubic root of 78390874 is about 427.9783849392.

The spelling of 78390874 in words is "seventy-eight million, three hundred ninety thousand, eight hundred seventy-four".