77681617 has 4 divisors (see below), whose sum is σ = 83657140. Its totient is φ = 71706096.

The previous prime is 77681579. The next prime is 77681641. The reversal of 77681617 is 71618677.

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 3101121 + 74580496 = 1761^2 + 8636^2 .

It is a cyclic number.

It is not a de Polignac number, because 77681617 - 2¹⁵ = 77648849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77681017) 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, 2987742 + ... + 2987767.

It is an arithmetic number, because the mean of its divisors is an integer number (20914285).

Almost surely, 2^77681617 is an apocalyptic number.

It is an amenable number.

77681617 is a deficient number, since it is larger than the sum of its proper divisors (5975523).

77681617 is a wasteful number, since it uses less digits than its factorization.

77681617 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5975522.

The product of its digits is 98784, while the sum is 43.

The square root of 77681617 is about 8813.7175470967. The cubic root of 77681617 is about 426.6837327022.

The spelling of 77681617 in words is "seventy-seven million, six hundred eighty-one thousand, six hundred seventeen".