721522368 has 168 divisors, whose sum is σ = 2381402400. Its totient is φ = 204595200.

The previous prime is 721522343. The next prime is 721522393. The reversal of 721522368 is 863225127.

721522368 is a `hidden beast` number, since 72 + 1 + 522 + 3 + 68 = 666.

It is an interprime number because it is at equal distance from previous prime (721522343) and next prime (721522393).

It is a tau number, because it is divible by the number of its divisors (168).

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

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 600168 + ... + 601368.

Almost surely, 2^721522368 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 721522368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1190701200).

721522368 is an abundant number, since it is smaller than the sum of its proper divisors (1659880032).

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

721522368 is a wasteful number, since it uses less digits than its factorization.

721522368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1375 (or 1362 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 721522368 is about 26861.1684034779. The cubic root of 721522368 is about 896.9122034254.

The spelling of 721522368 in words is "seven hundred twenty-one million, five hundred twenty-two thousand, three hundred sixty-eight".