721561255 has 8 divisors (see below), whose sum is σ = 886992624. Its totient is φ = 563169600.

The previous prime is 721561229. The next prime is 721561259. The reversal of 721561255 is 552165127.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 721561255 - 2⁵ = 721561223 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 721561255.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721561259) 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 7 ways as a sum of consecutive naturals, for example, 1759701 + ... + 1760110.

It is an arithmetic number, because the mean of its divisors is an integer number (110874078).

Almost surely, 2^721561255 is an apocalyptic number.

721561255 is a deficient number, since it is larger than the sum of its proper divisors (165431369).

721561255 is a wasteful number, since it uses less digits than its factorization.

721561255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3519857.

The product of its digits is 21000, while the sum is 34.

The square root of 721561255 is about 26861.8922453352. The cubic root of 721561255 is about 896.9283163924.

The spelling of 721561255 in words is "seven hundred twenty-one million, five hundred sixty-one thousand, two hundred fifty-five".