721325813 has 8 divisors (see below), whose sum is σ = 791470008. Its totient is φ = 653275584.

The previous prime is 721325807. The next prime is 721325821. The reversal of 721325813 is 318523127.

It can be written as a sum of positive squares in 4 ways, for example, as 4318084 + 717007729 = 2078^2 + 26777^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 721325813 - 2¹⁴ = 721309429 is a prime.

It is a super-2 number, since 2×721325813² = 1040621857000221938, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 721325813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721325863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 522770 + ... + 524147.

It is an arithmetic number, because the mean of its divisors is an integer number (98933751).

Almost surely, 2^721325813 is an apocalyptic number.

It is an amenable number.

721325813 is a deficient number, since it is larger than the sum of its proper divisors (70144195).

721325813 is a wasteful number, since it uses less digits than its factorization.

721325813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1046983.

The product of its digits is 10080, while the sum is 32.

The square root of 721325813 is about 26857.5094340484. The cubic root of 721325813 is about 896.8307513011.

The spelling of 721325813 in words is "seven hundred twenty-one million, three hundred twenty-five thousand, eight hundred thirteen".