77870561 has 2 divisors, whose sum is σ = 77870562. Its totient is φ = 77870560.

The previous prime is 77870503. The next prime is 77870567. The reversal of 77870561 is 16507877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76020961 + 1849600 = 8719^2 + 1360^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77870561 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (77870567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38935280 + 38935281.

It is an arithmetic number, because the mean of its divisors is an integer number (38935281).

Almost surely, 2^77870561 is an apocalyptic number.

It is an amenable number.

77870561 is a deficient number, since it is larger than the sum of its proper divisors (1).

77870561 is an equidigital number, since it uses as much as digits as its factorization.

77870561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 82320, while the sum is 41.

The square root of 77870561 is about 8824.4297832778. The cubic root of 77870561 is about 427.0293917284.

The spelling of 77870561 in words is "seventy-seven million, eight hundred seventy thousand, five hundred sixty-one".