721157513 has 8 divisors (see below), whose sum is σ = 724031616. Its totient is φ = 718290000.

The previous prime is 721157501. The next prime is 721157533. The reversal of 721157513 is 315751127.

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

It is a cyclic number.

It is not a de Polignac number, because 721157513 - 2⁴ = 721157497 is a prime.

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 721157513.

It is not an unprimeable number, because it can be changed into a prime (721157533) 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, 345170 + ... + 347252.

It is an arithmetic number, because the mean of its divisors is an integer number (90503952).

Almost surely, 2^721157513 is an apocalyptic number.

It is an amenable number.

721157513 is a deficient number, since it is larger than the sum of its proper divisors (2874103).

721157513 is a wasteful number, since it uses less digits than its factorization.

721157513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3295.

The product of its digits is 7350, while the sum is 32.

The square root of 721157513 is about 26854.3760493518. The cubic root of 721157513 is about 896.7609962504.

The spelling of 721157513 in words is "seven hundred twenty-one million, one hundred fifty-seven thousand, five hundred thirteen".