77309981 has 4 divisors (see below), whose sum is σ = 88354272. Its totient is φ = 66265692.

The previous prime is 77309977. The next prime is 77309989. The reversal of 77309981 is 18990377.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 77309981 - 2² = 77309977 is a prime.

It is a super-2 number, since 2×77309981² = 11953666324440722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77309989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5522135 + ... + 5522148.

It is an arithmetic number, because the mean of its divisors is an integer number (22088568).

Almost surely, 2^77309981 is an apocalyptic number.

It is an amenable number.

77309981 is a deficient number, since it is larger than the sum of its proper divisors (11044291).

77309981 is a wasteful number, since it uses less digits than its factorization.

77309981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11044290.

The product of its (nonzero) digits is 95256, while the sum is 44.

The square root of 77309981 is about 8792.6094533989. The cubic root of 77309981 is about 426.0022133207.

The spelling of 77309981 in words is "seventy-seven million, three hundred nine thousand, nine hundred eighty-one".