721163520 has 576 divisors, whose sum is σ = 3202375680. Its totient is φ = 149299200.

The previous prime is 721163501. The next prime is 721163557. The reversal of 721163520 is 25361127.

It is a happy number.

721163520 is a `hidden beast` number, since 7 + 2 + 1 + 1 + 635 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a zygodrome in base 4.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2660985 + ... + 2661255.

It is an arithmetic number, because the mean of its divisors is an integer number (5559680).

Almost surely, 2^721163520 is an apocalyptic number.

721163520 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 721163520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1601187840).

721163520 is an abundant number, since it is smaller than the sum of its proper divisors (2481212160).

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

721163520 is a wasteful number, since it uses less digits than its factorization.

721163520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319 (or 299 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 721163520 is about 26854.4878930878. The cubic root of 721163520 is about 896.7634861496.

The spelling of 721163520 in words is "seven hundred twenty-one million, one hundred sixty-three thousand, five hundred twenty".