78664889 has 4 divisors (see below), whose sum is σ = 78713856. Its totient is φ = 78615924.

The previous prime is 78664871. The next prime is 78664891. The reversal of 78664889 is 98846687.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78664889 is a prime.

It is a super-2 number, since 2×78664889² = 12376329522764642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78664829) 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, 21989 + ... + 25314.

It is an arithmetic number, because the mean of its divisors is an integer number (19678464).

Almost surely, 2^78664889 is an apocalyptic number.

It is an amenable number.

78664889 is a deficient number, since it is larger than the sum of its proper divisors (48967).

78664889 is a wasteful number, since it uses less digits than its factorization.

78664889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48966.

The product of its digits is 4644864, while the sum is 56.

The square root of 78664889 is about 8869.3229166605. The cubic root of 78664889 is about 428.4764706391.

The spelling of 78664889 in words is "seventy-eight million, six hundred sixty-four thousand, eight hundred eighty-nine".