78403664 has 20 divisors (see below), whose sum is σ = 152291220. Its totient is φ = 39102720.

The previous prime is 78403627. The next prime is 78403673. The reversal of 78403664 is 46630487.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 73960000 + 4443664 = 8600^2 + 2108^2 .

It is a super-2 number, since 2×78403664² = 12294269057249792, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 554 + ... + 12534.

It is an arithmetic number, because the mean of its divisors is an integer number (7614561).

Almost surely, 2^78403664 is an apocalyptic number.

It is an amenable number.

78403664 is a deficient number, since it is larger than the sum of its proper divisors (73887556).

78403664 is a wasteful number, since it uses less digits than its factorization.

78403664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12398 (or 12392 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 38.

The square root of 78403664 is about 8854.5843493639. The cubic root of 78403664 is about 428.0016595271.

The spelling of 78403664 in words is "seventy-eight million, four hundred three thousand, six hundred sixty-four".