78964921 has 6 divisors (see below), whose sum is σ = 91857210. Its totient is φ = 67684176.

The previous prime is 78964913. The next prime is 78964933. The reversal of 78964921 is 12946987.

It can be written as a sum of positive squares in only one way, i.e., 75951225 + 3013696 = 8715^2 + 1736^2 .

It is not a de Polignac number, because 78964921 - 2³ = 78964913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78964981) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 805716 + ... + 805813.

It is an arithmetic number, because the mean of its divisors is an integer number (15309535).

Almost surely, 2^78964921 is an apocalyptic number.

It is an amenable number.

78964921 is a deficient number, since it is larger than the sum of its proper divisors (12892289).

78964921 is a wasteful number, since it uses less digits than its factorization.

78964921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1611543 (or 1611536 counting only the distinct ones).

The product of its digits is 217728, while the sum is 46.

The square root of 78964921 is about 8886.2208502828. The cubic root of 78964921 is about 429.0205234303.

The spelling of 78964921 in words is "seventy-eight million, nine hundred sixty-four thousand, nine hundred twenty-one".