721944289 has 4 divisors (see below), whose sum is σ = 787575600. Its totient is φ = 656312980.

The previous prime is 721944281. The next prime is 721944317. The reversal of 721944289 is 982449127.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 721944289 - 2³ = 721944281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721944281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32815639 + ... + 32815660.

It is an arithmetic number, because the mean of its divisors is an integer number (196893900).

Almost surely, 2^721944289 is an apocalyptic number.

It is an amenable number.

721944289 is a deficient number, since it is larger than the sum of its proper divisors (65631311).

721944289 is a wasteful number, since it uses less digits than its factorization.

721944289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65631310.

The product of its digits is 290304, while the sum is 46.

The square root of 721944289 is about 26869.0209907246. The cubic root of 721944289 is about 897.0869969690.

The spelling of 721944289 in words is "seven hundred twenty-one million, nine hundred forty-four thousand, two hundred eighty-nine".