77963662681 has 4 divisors (see below), whose sum is σ = 77970689332. Its totient is φ = 77956636032.

The previous prime is 77963662661. The next prime is 77963662687. The reversal of 77963662681 is 18626636977.

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 406425600 + 77557237081 = 20160^2 + 278491^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77963662681 is a prime.

It is a super-2 number, since 2×77963662681² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77963662687) 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, 3496656 + ... + 3518881.

It is an arithmetic number, because the mean of its divisors is an integer number (19492672333).

Almost surely, 2^77963662681 is an apocalyptic number.

It is an amenable number.

77963662681 is a deficient number, since it is larger than the sum of its proper divisors (7026651).

77963662681 is a wasteful number, since it uses less digits than its factorization.

77963662681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7026650.

The product of its digits is 27433728, while the sum is 61.

The spelling of 77963662681 in words is "seventy-seven billion, nine hundred sixty-three million, six hundred sixty-two thousand, six hundred eighty-one".