77887320889 has 9 divisors (see below), whose sum is σ = 90605890767. Its totient is φ = 66758886264.

The previous prime is 77887320869. The next prime is 77887320919. The reversal of 77887320889 is 98802378877.

The square root of 77887320889 is 279083.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 44303093289 + 33584227600 = 210483^2 + 183260^2 .

It is not a de Polignac number, because 77887320889 - 2⁷ = 77887320761 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77887320809) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1933647 + ... + 1973515.

Almost surely, 2^77887320889 is an apocalyptic number.

77887320889 is the 279083-rd square number.

77887320889 is the 139542-nd centered octagonal number.

It is an amenable number.

77887320889 is a deficient number, since it is larger than the sum of its proper divisors (12718569878).

77887320889 is an frugal number, since it uses more digits than its factorization.

77887320889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79752 (or 39876 counting only the distinct ones).

The product of its (nonzero) digits is 75866112, while the sum is 67.

The spelling of 77887320889 in words is "seventy-seven billion, eight hundred eighty-seven million, three hundred twenty thousand, eight hundred eighty-nine".