77897598991 has 4 divisors (see below), whose sum is σ = 78028961472. Its totient is φ = 77766236512.

The previous prime is 77897598971. The next prime is 77897599001. The reversal of 77897598991 is 19989579877.

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

It is a cyclic number.

It is not a de Polignac number, because 77897598991 - 2²¹ = 77895501839 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 (77897598931) 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, 65680351 + ... + 65681536.

It is an arithmetic number, because the mean of its divisors is an integer number (19507240368).

Almost surely, 2^77897598991 is an apocalyptic number.

77897598991 is a deficient number, since it is larger than the sum of its proper divisors (131362481).

77897598991 is a wasteful number, since it uses less digits than its factorization.

77897598991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131362480.

The product of its digits is 720135360, while the sum is 79.

The spelling of 77897598991 in words is "seventy-seven billion, eight hundred ninety-seven million, five hundred ninety-eight thousand, nine hundred ninety-one".