76809721 has 2 divisors, whose sum is σ = 76809722. Its totient is φ = 76809720.

The previous prime is 76809701. The next prime is 76809781. The reversal of 76809721 is 12790867.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 76807696 + 2025 = 8764^2 + 45^2 .

It is a cyclic number.

It is not a de Polignac number, because 76809721 - 2¹¹ = 76807673 is a prime.

It is not a weakly prime, because it can be changed into another prime (76809701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38404860 + 38404861.

It is an arithmetic number, because the mean of its divisors is an integer number (38404861).

Almost surely, 2^76809721 is an apocalyptic number.

It is an amenable number.

76809721 is a deficient number, since it is larger than the sum of its proper divisors (1).

76809721 is an equidigital number, since it uses as much as digits as its factorization.

76809721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 76809721 is about 8764.1155286772. The cubic root of 76809721 is about 425.0813611247.

The spelling of 76809721 in words is "seventy-six million, eight hundred nine thousand, seven hundred twenty-one".