77766691 has 4 divisors (see below), whose sum is σ = 77792112. Its totient is φ = 77741272.

The previous prime is 77766683. The next prime is 77766701. The reversal of 77766691 is 19666777.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19666777 = 13 ⋅1512829.

It is a cyclic number.

It is not a de Polignac number, because 77766691 - 2³ = 77766683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77766641) 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, 7375 + ... + 14488.

It is an arithmetic number, because the mean of its divisors is an integer number (19448028).

Almost surely, 2^77766691 is an apocalyptic number.

77766691 is a deficient number, since it is larger than the sum of its proper divisors (25421).

77766691 is a wasteful number, since it uses less digits than its factorization.

77766691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25420.

The product of its digits is 666792, while the sum is 49.

The square root of 77766691 is about 8818.5424532629. The cubic root of 77766691 is about 426.8394385607.

The spelling of 77766691 in words is "seventy-seven million, seven hundred sixty-six thousand, six hundred ninety-one".