721608779 has 2 divisors, whose sum is σ = 721608780. Its totient is φ = 721608778.

The previous prime is 721608737. The next prime is 721608781. The reversal of 721608779 is 977806127.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 721608779 - 2²⁴ = 704831563 is a prime.

Together with 721608781, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (721608379) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360804389 + 360804390.

It is an arithmetic number, because the mean of its divisors is an integer number (360804390).

Almost surely, 2^721608779 is an apocalyptic number.

721608779 is a deficient number, since it is larger than the sum of its proper divisors (1).

721608779 is an equidigital number, since it uses as much as digits as its factorization.

721608779 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 296352, while the sum is 47.

The square root of 721608779 is about 26862.7768296578. The cubic root of 721608779 is about 896.9480073451.

The spelling of 721608779 in words is "seven hundred twenty-one million, six hundred eight thousand, seven hundred seventy-nine".