78388644 has 24 divisors (see below), whose sum is σ = 187851328. Its totient is φ = 25423200.

The previous prime is 78388637. The next prime is 78388657. The reversal of 78388644 is 44688387.

It is a super-2 number, since 2×78388644² = 12289559016317472, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78388593 and 78388602.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87832 + ... + 88719.

Almost surely, 2^78388644 is an apocalyptic number.

78388644 is a gapful number since it is divisible by the number (74) formed by its first and last digit.

It is an amenable number.

78388644 is an abundant number, since it is smaller than the sum of its proper divisors (109462684).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78388644 is a wasteful number, since it uses less digits than its factorization.

78388644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176595 (or 176593 counting only the distinct ones).

The product of its digits is 1032192, while the sum is 48.

The square root of 78388644 is about 8853.7361605144. The cubic root of 78388644 is about 427.9743266401.

The spelling of 78388644 in words is "seventy-eight million, three hundred eighty-eight thousand, six hundred forty-four".