721768320 has 896 divisors, whose sum is σ = 3371336640. Its totient is φ = 143327232.

The previous prime is 721768291. The next prime is 721768351. The reversal of 721768320 is 23867127.

It is a tau number, because it is divible by the number of its divisors (896).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 111 ways as a sum of consecutive naturals, for example, 42456952 + ... + 42456968.

Almost surely, 2^721768320 is an apocalyptic number.

721768320 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 721768320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1685668320).

721768320 is an abundant number, since it is smaller than the sum of its proper divisors (2649568320).

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

721768320 is a wasteful number, since it uses less digits than its factorization.

721768320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 36.

The square root of 721768320 is about 26865.7462207920. The cubic root of 721768320 is about 897.0141047659.

The spelling of 721768320 in words is "seven hundred twenty-one million, seven hundred sixty-eight thousand, three hundred twenty".