721792128 has 64 divisors (see below), whose sum is σ = 1926086400. Its totient is φ = 239490048.

The previous prime is 721792091. The next prime is 721792129. The reversal of 721792128 is 821297127.

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (721792129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81418 + ... + 89846.

It is an arithmetic number, because the mean of its divisors is an integer number (30095100).

Almost surely, 2^721792128 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 721792128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (963043200).

721792128 is an abundant number, since it is smaller than the sum of its proper divisors (1204294272).

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

721792128 is a wasteful number, since it uses less digits than its factorization.

721792128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8669 (or 8657 counting only the distinct ones).

The product of its digits is 28224, while the sum is 39.

The square root of 721792128 is about 26866.1893092415. The cubic root of 721792128 is about 897.0239675230.

The spelling of 721792128 in words is "seven hundred twenty-one million, seven hundred ninety-two thousand, one hundred twenty-eight".