721513408 has 112 divisors (see below), whose sum is σ = 1829092608. Its totient is φ = 274176000.

The previous prime is 721513361. The next prime is 721513423. The reversal of 721513408 is 804315127.

It is a tau number, because it is divible by the number of its divisors (112).

It is a self number, because there is not a number n which added to its sum of digits gives 721513408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 200263 + ... + 203833.

It is an arithmetic number, because the mean of its divisors is an integer number (16331184).

Almost surely, 2^721513408 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 721513408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (914546304).

721513408 is an abundant number, since it is smaller than the sum of its proper divisors (1107579200).

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

721513408 is a wasteful number, since it uses less digits than its factorization.

721513408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3642 (or 3632 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 721513408 is about 26861.0016194482. The cubic root of 721513408 is about 896.9084907354.

The spelling of 721513408 in words is "seven hundred twenty-one million, five hundred thirteen thousand, four hundred eight".