77057721 has 12 divisors (see below), whose sum is σ = 119867748. Its totient is φ = 47420064.

The previous prime is 77057693. The next prime is 77057741. The reversal of 77057721 is 12775077.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 32901696 + 44156025 = 5736^2 + 6645^2 .

It is not a de Polignac number, because 77057721 - 2⁶ = 77057657 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (77057741) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 329190 + ... + 329423.

It is an arithmetic number, because the mean of its divisors is an integer number (9988979).

Almost surely, 2^77057721 is an apocalyptic number.

It is an amenable number.

77057721 is a deficient number, since it is larger than the sum of its proper divisors (42810027).

77057721 is a wasteful number, since it uses less digits than its factorization.

77057721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 658632 (or 658629 counting only the distinct ones).

The product of its (nonzero) digits is 24010, while the sum is 36.

The square root of 77057721 is about 8778.2527304698. The cubic root of 77057721 is about 425.5383645722.

The spelling of 77057721 in words is "seventy-seven million, fifty-seven thousand, seven hundred twenty-one".