77718989 has 4 divisors (see below), whose sum is σ = 79036320. Its totient is φ = 76401660.

The previous prime is 77718937. The next prime is 77718997. The reversal of 77718989 is 98981777.

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 not a de Polignac number, because 77718989 - 2⁸ = 77718733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77718089) 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, 658577 + ... + 658694.

It is an arithmetic number, because the mean of its divisors is an integer number (19759080).

Almost surely, 2^77718989 is an apocalyptic number.

It is an amenable number.

77718989 is a deficient number, since it is larger than the sum of its proper divisors (1317331).

77718989 is a wasteful number, since it uses less digits than its factorization.

77718989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1317330.

The product of its digits is 1778112, while the sum is 56.

The square root of 77718989 is about 8815.8373964133. The cubic root of 77718989 is about 426.7521464342.

The spelling of 77718989 in words is "seventy-seven million, seven hundred eighteen thousand, nine hundred eighty-nine".