721000913 has 2 divisors, whose sum is σ = 721000914. Its totient is φ = 721000912.

The previous prime is 721000901. The next prime is 721000919. The reversal of 721000913 is 319000127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 677665024 + 43335889 = 26032^2 + 6583^2 .

It is an emirp because it is prime and its reverse (319000127) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721000913 is a prime.

It is not a weakly prime, because it can be changed into another prime (721000919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360500456 + 360500457.

It is an arithmetic number, because the mean of its divisors is an integer number (360500457).

Almost surely, 2^721000913 is an apocalyptic number.

It is an amenable number.

721000913 is a deficient number, since it is larger than the sum of its proper divisors (1).

721000913 is an equidigital number, since it uses as much as digits as its factorization.

721000913 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 378, while the sum is 23.

The square root of 721000913 is about 26851.4601651381. The cubic root of 721000913 is about 896.6960807335.

The spelling of 721000913 in words is "seven hundred twenty-one million, nine hundred thirteen", and thus it is an aban number.