721891560 has 128 divisors (see below), whose sum is σ = 2340576000. Its totient is φ = 177063936.

The previous prime is 721891537. The next prime is 721891561. The reversal of 721891560 is 65198127.

It is a super-2 number, since 2×721891560² = 1042254848798467200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (721891561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 559396 + ... + 560684.

It is an arithmetic number, because the mean of its divisors is an integer number (18285750).

Almost surely, 2^721891560 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 721891560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1170288000).

721891560 is an abundant number, since it is smaller than the sum of its proper divisors (1618684440).

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

721891560 is a wasteful number, since it uses less digits than its factorization.

721891560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1675 (or 1671 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 39.

The square root of 721891560 is about 26868.0397498589. The cubic root of 721891560 is about 897.0651561092.

The spelling of 721891560 in words is "seven hundred twenty-one million, eight hundred ninety-one thousand, five hundred sixty".