77769991 has 4 divisors (see below), whose sum is σ = 83752312. Its totient is φ = 71787672.

The previous prime is 77769959. The next prime is 77770009. The reversal of 77769991 is 19996777.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 77769991 - 2⁵ = 77769959 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 (77769911) 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, 2991141 + ... + 2991166.

It is an arithmetic number, because the mean of its divisors is an integer number (20938078).

Almost surely, 2^77769991 is an apocalyptic number.

77769991 is a deficient number, since it is larger than the sum of its proper divisors (5982321).

77769991 is a wasteful number, since it uses less digits than its factorization.

77769991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5982320.

The product of its digits is 1500282, while the sum is 55.

The square root of 77769991 is about 8818.7295570280. The cubic root of 77769991 is about 426.8454760651.

The spelling of 77769991 in words is "seventy-seven million, seven hundred sixty-nine thousand, nine hundred ninety-one".