721185920 has 384 divisors, whose sum is σ = 2270948400. Its totient is φ = 216760320.

The previous prime is 721185919. The next prime is 721185943. The reversal of 721185920 is 29581127.

It can be written as a sum of positive squares in 8 ways, for example, as 37258816 + 683927104 = 6104^2 + 26152^2 .

It is a Harshad number since it is a multiple of its sum of digits (35).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11822690 + ... + 11822750.

Almost surely, 2^721185920 is an apocalyptic number.

721185920 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721185920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1135474200).

721185920 is an abundant number, since it is smaller than the sum of its proper divisors (1549762480).

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

721185920 is a wasteful number, since it uses less digits than its factorization.

721185920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 35.

The square root of 721185920 is about 26854.9049523546. The cubic root of 721185920 is about 896.7727708187.

The spelling of 721185920 in words is "seven hundred twenty-one million, one hundred eighty-five thousand, nine hundred twenty".