721553520 has 160 divisors (see below), whose sum is σ = 2323851264. Its totient is φ = 185011200.

The previous prime is 721553507. The next prime is 721553543. The reversal of 721553520 is 25355127.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2179755 + ... + 2180085.

Almost surely, 2^721553520 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 721553520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1161925632).

721553520 is an abundant number, since it is smaller than the sum of its proper divisors (1602297744).

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

721553520 is a wasteful number, since it uses less digits than its factorization.

721553520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 671 (or 665 counting only the distinct ones).

The product of its (nonzero) digits is 10500, while the sum is 30.

The square root of 721553520 is about 26861.7482677506. The cubic root of 721553520 is about 896.9251114137.

The spelling of 721553520 in words is "seven hundred twenty-one million, five hundred fifty-three thousand, five hundred twenty".