77981331 has 4 divisors (see below), whose sum is σ = 103975112. Its totient is φ = 51987552.

The previous prime is 77981297. The next prime is 77981333. The reversal of 77981331 is 13318977.

It is a happy number.

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

It is not a de Polignac number, because 77981331 - 2¹¹ = 77979283 is a prime.

It is a super-2 number, since 2×77981331² = 12162175969063122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 77981331.

It is not an unprimeable number, because it can be changed into a prime (77981333) 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, 12996886 + ... + 12996891.

It is an arithmetic number, because the mean of its divisors is an integer number (25993778).

Almost surely, 2^77981331 is an apocalyptic number.

77981331 is a deficient number, since it is larger than the sum of its proper divisors (25993781).

77981331 is a wasteful number, since it uses less digits than its factorization.

77981331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25993780.

The product of its digits is 31752, while the sum is 39.

The square root of 77981331 is about 8830.7038790801. The cubic root of 77981331 is about 427.2317773024.

The spelling of 77981331 in words is "seventy-seven million, nine hundred eighty-one thousand, three hundred thirty-one".