77138381 has 4 divisors (see below), whose sum is σ = 77179452. Its totient is φ = 77097312.

The previous prime is 77138371. The next prime is 77138387. The reversal of 77138381 is 18383177.

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

It can be written as a sum of positive squares in 2 ways, for example, as 23716900 + 53421481 = 4870^2 + 7309^2 .

It is a cyclic number.

It is not a de Polignac number, because 77138381 - 2¹⁴ = 77121997 is a prime.

It is a super-2 number, since 2×77138381² = 11900659646602322, 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 (77138387) 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, 17576 + ... + 21521.

It is an arithmetic number, because the mean of its divisors is an integer number (19294863).

Almost surely, 2^77138381 is an apocalyptic number.

It is an amenable number.

77138381 is a deficient number, since it is larger than the sum of its proper divisors (41071).

77138381 is a wasteful number, since it uses less digits than its factorization.

77138381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41070.

The product of its digits is 28224, while the sum is 38.

The square root of 77138381 is about 8782.8458371988. The cubic root of 77138381 is about 425.6867899120.

The spelling of 77138381 in words is "seventy-seven million, one hundred thirty-eight thousand, three hundred eighty-one".