721751056 has 20 divisors (see below), whose sum is σ = 1505961772. Its totient is φ = 333115776.

The previous prime is 721751053. The next prime is 721751057. The reversal of 721751056 is 650157127.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 37405456 + 684345600 = 6116^2 + 26160^2 .

It is not an unprimeable number, because it can be changed into a prime (721751053) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1734771 + ... + 1735186.

Almost surely, 2^721751056 is an apocalyptic number.

It is an amenable number.

721751056 is an abundant number, since it is smaller than the sum of its proper divisors (784210716).

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

721751056 is a wasteful number, since it uses less digits than its factorization.

721751056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3469978 (or 3469972 counting only the distinct ones).

The product of its (nonzero) digits is 14700, while the sum is 34.

The square root of 721751056 is about 26865.4249175404. The cubic root of 721751056 is about 897.0069528056.

The spelling of 721751056 in words is "seven hundred twenty-one million, seven hundred fifty-one thousand, fifty-six".