721454721 has 64 divisors (see below), whose sum is σ = 1146700800. Its totient is φ = 399200256.

The previous prime is 721454717. The next prime is 721454753. The reversal of 721454721 is 127454127.

It is not a de Polignac number, because 721454721 - 2² = 721454717 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (721454711) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3018520 + ... + 3018758.

It is an arithmetic number, because the mean of its divisors is an integer number (17917200).

Almost surely, 2^721454721 is an apocalyptic number.

It is an amenable number.

721454721 is a deficient number, since it is larger than the sum of its proper divisors (425246079).

721454721 is a wasteful number, since it uses less digits than its factorization.

721454721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 458.

The product of its digits is 15680, while the sum is 33.

The square root of 721454721 is about 26859.9091770616. The cubic root of 721454721 is about 896.8841722704.

The spelling of 721454721 in words is "seven hundred twenty-one million, four hundred fifty-four thousand, seven hundred twenty-one".