77680381 has 4 divisors (see below), whose sum is σ = 78367932. Its totient is φ = 76992832.

The previous prime is 77680373. The next prime is 77680391. The reversal of 77680381 is 18308677.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18308677 = 17 ⋅1076981.

It can be written as a sum of positive squares in 2 ways, for example, as 42693156 + 34987225 = 6534^2 + 5915^2 .

It is a cyclic number.

It is not a de Polignac number, because 77680381 - 2³ = 77680373 is a prime.

It is a super-2 number, since 2×77680381² = 12068483184610322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77680301) 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, 343606 + ... + 343831.

It is an arithmetic number, because the mean of its divisors is an integer number (19591983).

Almost surely, 2^77680381 is an apocalyptic number.

It is an amenable number.

77680381 is a deficient number, since it is larger than the sum of its proper divisors (687551).

77680381 is a wasteful number, since it uses less digits than its factorization.

77680381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 687550.

The product of its (nonzero) digits is 56448, while the sum is 40.

The square root of 77680381 is about 8813.6474288458. The cubic root of 77680381 is about 426.6814696877.

The spelling of 77680381 in words is "seventy-seven million, six hundred eighty thousand, three hundred eighty-one".