78400647 has 24 divisors (see below), whose sum is σ = 122426304. Its totient is φ = 48060864.

The previous prime is 78400639. The next prime is 78400649. The reversal of 78400647 is 74600487.

It is a happy number.

78400647 is a `hidden beast` number, since 7 + 8 + 4 + 0 + 0 + 647 = 666.

It is not a de Polignac number, because 78400647 - 2³ = 78400639 is a prime.

It is a super-2 number, since 2×78400647² = 12293322900037218, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78400649) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33138 + ... + 35424.

It is an arithmetic number, because the mean of its divisors is an integer number (5101096).

Almost surely, 2^78400647 is an apocalyptic number.

78400647 is a deficient number, since it is larger than the sum of its proper divisors (44025657).

78400647 is a wasteful number, since it uses less digits than its factorization.

78400647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2599 (or 2596 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 36.

The square root of 78400647 is about 8854.4139839969. The cubic root of 78400647 is about 427.9961695730.

The spelling of 78400647 in words is "seventy-eight million, four hundred thousand, six hundred forty-seven".