721392 has 80 divisors (see below), whose sum is σ = 2261760. Its totient is φ = 193536.

The previous prime is 721387. The next prime is 721397. The reversal of 721392 is 293127.

It is an interprime number because it is at equal distance from previous prime (721387) and next prime (721397).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 721392.

It is not an unprimeable number, because it can be changed into a prime (721397) by changing a digit.

721392 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6328 + ... + 6440.

It is an arithmetic number, because the mean of its divisors is an integer number (28272).

2⁷²¹³⁹² 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 721392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1130880).

721392 is an abundant number, since it is smaller than the sum of its proper divisors (1540368).

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

721392 is a wasteful number, since it uses less digits than its factorization.

721392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150 (or 144 counting only the distinct ones).

The product of its digits is 756, while the sum is 24.

The square root of 721392 is about 849.3479852216. The cubic root of 721392 is about 89.6858180756.

The spelling of 721392 in words is "seven hundred twenty-one thousand, three hundred ninety-two".