77992661 has 8 divisors (see below), whose sum is σ = 79061400. Its totient is φ = 76930560.

The previous prime is 77992657. The next prime is 77992667. The reversal of 77992661 is 16629977.

It can be written as a sum of positive squares in 4 ways, for example, as 5640625 + 72352036 = 2375^2 + 8506^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 77992661 - 2² = 77992657 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 (77992667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24785 + ... + 27753.

It is an arithmetic number, because the mean of its divisors is an integer number (9882675).

Almost surely, 2^77992661 is an apocalyptic number.

It is an amenable number.

77992661 is a deficient number, since it is larger than the sum of its proper divisors (1068739).

77992661 is a wasteful number, since it uses less digits than its factorization.

77992661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3319.

The product of its digits is 285768, while the sum is 47.

The square root of 77992661 is about 8831.3453674964. The cubic root of 77992661 is about 427.2524673042.

The spelling of 77992661 in words is "seventy-seven million, nine hundred ninety-two thousand, six hundred sixty-one".