77764681 has 4 divisors (see below), whose sum is σ = 82339092. Its totient is φ = 73190272.

The previous prime is 77764657. The next prime is 77764693. The reversal of 77764681 is 18646777.

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

It can be written as a sum of positive squares in 2 ways, for example, as 47734281 + 30030400 = 6909^2 + 5480^2 .

It is a cyclic number.

It is not a de Polignac number, because 77764681 - 2⁷ = 77764553 is a prime.

It is a super-2 number, since 2×77764681² = 12094691222063522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (77764651) 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, 2287180 + ... + 2287213.

It is an arithmetic number, because the mean of its divisors is an integer number (20584773).

Almost surely, 2^77764681 is an apocalyptic number.

It is an amenable number.

77764681 is a deficient number, since it is larger than the sum of its proper divisors (4574411).

77764681 is a wasteful number, since it uses less digits than its factorization.

77764681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4574410.

The product of its digits is 395136, while the sum is 46.

The square root of 77764681 is about 8818.4284881151. The cubic root of 77764681 is about 426.8357610879.

The spelling of 77764681 in words is "seventy-seven million, seven hundred sixty-four thousand, six hundred eighty-one".