77764813 has 12 divisors (see below), whose sum is σ = 91947612. Its totient is φ = 65560320.

The previous prime is 77764807. The next prime is 77764847. The reversal of 77764813 is 31846777.

It can be written as a sum of positive squares in 2 ways, for example, as 26183689 + 51581124 = 5117^2 + 7182^2 .

It is not a de Polignac number, because 77764813 - 2⁵ = 77764781 is a prime.

It is a super-2 number, since 2×77764813² = 12094732281849938, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 77764813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77764013) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10020 + ... + 15997.

It is an arithmetic number, because the mean of its divisors is an integer number (7662301).

Almost surely, 2^77764813 is an apocalyptic number.

It is an amenable number.

77764813 is a deficient number, since it is larger than the sum of its proper divisors (14182799).

77764813 is a wasteful number, since it uses less digits than its factorization.

77764813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26092 (or 26085 counting only the distinct ones).

The product of its digits is 197568, while the sum is 43.

The square root of 77764813 is about 8818.4359724387. The cubic root of 77764813 is about 426.8360025955.

The spelling of 77764813 in words is "seventy-seven million, seven hundred sixty-four thousand, eight hundred thirteen".