78020644 has 12 divisors (see below), whose sum is σ = 147039004. Its totient is φ = 36009504.

The previous prime is 78020641. The next prime is 78020659. The reversal of 78020644 is 44602087.

It can be written as a sum of positive squares in 2 ways, for example, as 16711744 + 61308900 = 4088^2 + 7830^2 .

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (78020641) 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, 750147 + ... + 750250.

Almost surely, 2^78020644 is an apocalyptic number.

It is an amenable number.

78020644 is a deficient number, since it is larger than the sum of its proper divisors (69018360).

78020644 is a wasteful number, since it uses less digits than its factorization.

78020644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1500414 (or 1500412 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 31.

The square root of 78020644 is about 8832.9295253613. The cubic root of 78020644 is about 427.3035591892.

The spelling of 78020644 in words is "seventy-eight million, twenty thousand, six hundred forty-four".