721017491 has 8 divisors (see below), whose sum is σ = 759270480. Its totient is φ = 682795008.

The previous prime is 721017461. The next prime is 721017527. The reversal of 721017491 is 194710127.

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 721017491 - 2¹⁴ = 721001107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721017461) 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, 53555 + ... + 65651.

It is an arithmetic number, because the mean of its divisors is an integer number (94908810).

Almost surely, 2^721017491 is an apocalyptic number.

721017491 is a deficient number, since it is larger than the sum of its proper divisors (38252989).

721017491 is a wasteful number, since it uses less digits than its factorization.

721017491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15253.

The product of its (nonzero) digits is 3528, while the sum is 32.

The square root of 721017491 is about 26851.7688616597. The cubic root of 721017491 is about 896.7029532693.

The spelling of 721017491 in words is "seven hundred twenty-one million, seventeen thousand, four hundred ninety-one".