721568491 has 8 divisors (see below), whose sum is σ = 868052480. Its totient is φ = 585935208.

The previous prime is 721568483. The next prime is 721568513. The reversal of 721568491 is 194865127.

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 721568491 - 2³ = 721568483 is a prime.

It is a super-2 number, since 2×721568491² = 1041322174408034162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721568461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2712531 + ... + 2712796.

It is an arithmetic number, because the mean of its divisors is an integer number (108506560).

Almost surely, 2^721568491 is an apocalyptic number.

721568491 is a deficient number, since it is larger than the sum of its proper divisors (146483989).

721568491 is a wasteful number, since it uses less digits than its factorization.

721568491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5425353.

The product of its digits is 120960, while the sum is 43.

The square root of 721568491 is about 26862.0269339452. The cubic root of 721568491 is about 896.9313145909.

The spelling of 721568491 in words is "seven hundred twenty-one million, five hundred sixty-eight thousand, four hundred ninety-one".