77881761 has 6 divisors (see below), whose sum is σ = 112495890. Its totient is φ = 51921168.

The previous prime is 77881759. The next prime is 77881789. The reversal of 77881761 is 16718877.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 72846225 + 5035536 = 8535^2 + 2244^2 .

It is not a de Polignac number, because 77881761 - 2¹ = 77881759 is a prime.

It is a super-2 number, since 2×77881761² = 12131137392922242, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (77881061) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4326756 + ... + 4326773.

It is an arithmetic number, because the mean of its divisors is an integer number (18749315).

Almost surely, 2^77881761 is an apocalyptic number.

It is an amenable number.

77881761 is a deficient number, since it is larger than the sum of its proper divisors (34614129).

77881761 is a wasteful number, since it uses less digits than its factorization.

77881761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8653535 (or 8653532 counting only the distinct ones).

The product of its digits is 131712, while the sum is 45.

The square root of 77881761 is about 8825.0643623715. The cubic root of 77881761 is about 427.0498637350.

The spelling of 77881761 in words is "seventy-seven million, eight hundred eighty-one thousand, seven hundred sixty-one".