77905681 has 8 divisors (see below), whose sum is σ = 93721280. Its totient is φ = 63261648.

The previous prime is 77905627. The next prime is 77905691. The reversal of 77905681 is 18650977.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77905681 is a prime.

It is a super-2 number, since 2×77905681² = 12138590264147522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77905621) 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 7 ways as a sum of consecutive naturals, for example, 292746 + ... + 293011.

It is an arithmetic number, because the mean of its divisors is an integer number (11715160).

Almost surely, 2^77905681 is an apocalyptic number.

It is an amenable number.

77905681 is a deficient number, since it is larger than the sum of its proper divisors (15815599).

77905681 is a wasteful number, since it uses less digits than its factorization.

77905681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 585783.

The product of its (nonzero) digits is 105840, while the sum is 43.

The square root of 77905681 is about 8826.4194892380. The cubic root of 77905681 is about 427.0935795207.

The spelling of 77905681 in words is "seventy-seven million, nine hundred five thousand, six hundred eighty-one".