721707313 has 4 divisors (see below), whose sum is σ = 738491248. Its totient is φ = 704923380.

The previous prime is 721707299. The next prime is 721707323. The reversal of 721707313 is 313707127.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 313707127 = 37 ⋅8478571.

It is a cyclic number.

It is not a de Polignac number, because 721707313 - 2⁵ = 721707281 is a prime.

It is a super-2 number, since 2×721707313² = 1041722891275359938, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721707323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8391903 + ... + 8391988.

It is an arithmetic number, because the mean of its divisors is an integer number (184622812).

Almost surely, 2^721707313 is an apocalyptic number.

It is an amenable number.

721707313 is a deficient number, since it is larger than the sum of its proper divisors (16783935).

721707313 is a wasteful number, since it uses less digits than its factorization.

721707313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16783934.

The product of its (nonzero) digits is 6174, while the sum is 31.

The square root of 721707313 is about 26864.6107918950. The cubic root of 721707313 is about 896.9888308749.

The spelling of 721707313 in words is "seven hundred twenty-one million, seven hundred seven thousand, three hundred thirteen".