77506561 has 8 divisors (see below), whose sum is σ = 84777984. Its totient is φ = 70272720.

The previous prime is 77506501. The next prime is 77506571. The reversal of 77506561 is 16560577.

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

It is a cyclic number.

It is not a de Polignac number, because 77506561 - 2⁹ = 77506049 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 77506561.

It is not an unprimeable number, because it can be changed into a prime (77506501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4986 + ... + 13411.

It is an arithmetic number, because the mean of its divisors is an integer number (10597248).

Almost surely, 2^77506561 is an apocalyptic number.

It is an amenable number.

77506561 is a deficient number, since it is larger than the sum of its proper divisors (7271423).

77506561 is a wasteful number, since it uses less digits than its factorization.

77506561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18791.

The product of its (nonzero) digits is 44100, while the sum is 37.

The square root of 77506561 is about 8803.7810627025. The cubic root of 77506561 is about 426.3629801733.

The spelling of 77506561 in words is "seventy-seven million, five hundred six thousand, five hundred sixty-one".