721238320 has 80 divisors (see below), whose sum is σ = 1845765792. Its totient is φ = 259911680.

The previous prime is 721238303. The next prime is 721238333. The reversal of 721238320 is 23832127.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 95814 + ... + 103066.

Almost surely, 2^721238320 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721238320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (922882896).

721238320 is an abundant number, since it is smaller than the sum of its proper divisors (1124527472).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721238320 is a wasteful number, since it uses less digits than its factorization.

721238320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7390 (or 7384 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 721238320 is about 26855.8805478428. The cubic root of 721238320 is about 896.7944895618.

The spelling of 721238320 in words is "seven hundred twenty-one million, two hundred thirty-eight thousand, three hundred twenty".