77560921 has 2 divisors, whose sum is σ = 77560922. Its totient is φ = 77560920.

The previous prime is 77560891. The next prime is 77560937. The reversal of 77560921 is 12906577.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76317696 + 1243225 = 8736^2 + 1115^2 .

It is an emirp because it is prime and its reverse (12906577) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77560921 - 2¹³ = 77552729 is a prime.

It is not a weakly prime, because it can be changed into another prime (77560981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38780460 + 38780461.

It is an arithmetic number, because the mean of its divisors is an integer number (38780461).

Almost surely, 2^77560921 is an apocalyptic number.

It is an amenable number.

77560921 is a deficient number, since it is larger than the sum of its proper divisors (1).

77560921 is an equidigital number, since it uses as much as digits as its factorization.

77560921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26460, while the sum is 37.

The square root of 77560921 is about 8806.8678314143. The cubic root of 77560921 is about 426.4626348559.

The spelling of 77560921 in words is "seventy-seven million, five hundred sixty thousand, nine hundred twenty-one".