721055565 has 48 divisors (see below), whose sum is σ = 1296425520. Its totient is φ = 370298880.

The previous prime is 721055557. The next prime is 721055603. The reversal of 721055565 is 565550127.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 49364676 + 671690889 = 7026^2 + 25917^2 .

It is not a de Polignac number, because 721055565 - 2³ = 721055557 is a prime.

It is a super-2 number, since 2×721055565² = 1039842255634938450, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 877855 + ... + 878675.

It is an arithmetic number, because the mean of its divisors is an integer number (27008865).

Almost surely, 2^721055565 is an apocalyptic number.

It is an amenable number.

721055565 is a deficient number, since it is larger than the sum of its proper divisors (575369955).

721055565 is a wasteful number, since it uses less digits than its factorization.

721055565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1534 (or 1531 counting only the distinct ones).

The product of its (nonzero) digits is 52500, while the sum is 36.

The square root of 721055565 is about 26852.4778186297. The cubic root of 721055565 is about 896.7187367363.

The spelling of 721055565 in words is "seven hundred twenty-one million, fifty-five thousand, five hundred sixty-five".