77138581 has 8 divisors (see below), whose sum is σ = 83210904. Its totient is φ = 71086080.

The previous prime is 77138563. The next prime is 77138591. The reversal of 77138581 is 18583177.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2056356 + 75082225 = 1434^2 + 8665^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 77138581 - 2⁵ = 77138549 is a prime.

It is a super-2 number, since 2×77138581² = 11900721357387122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77138591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3705 + ... + 12961.

It is an arithmetic number, because the mean of its divisors is an integer number (10401363).

Almost surely, 2^77138581 is an apocalyptic number.

It is an amenable number.

77138581 is a deficient number, since it is larger than the sum of its proper divisors (6072323).

77138581 is a wasteful number, since it uses less digits than its factorization.

77138581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9911.

The product of its digits is 47040, while the sum is 40.

The square root of 77138581 is about 8782.8572230226. The cubic root of 77138581 is about 425.6871578105.

The spelling of 77138581 in words is "seventy-seven million, one hundred thirty-eight thousand, five hundred eighty-one".