721255745 has 24 divisors (see below), whose sum is σ = 1008008064. Its totient is φ = 493989216.

The previous prime is 721255729. The next prime is 721255757. The reversal of 721255745 is 547552127.

It is not a de Polignac number, because 721255745 - 2⁴ = 721255729 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 721255699 and 721255708.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 348584 + ... + 350646.

It is an arithmetic number, because the mean of its divisors is an integer number (42000336).

Almost surely, 2^721255745 is an apocalyptic number.

It is an amenable number.

721255745 is a deficient number, since it is larger than the sum of its proper divisors (286752319).

721255745 is a wasteful number, since it uses less digits than its factorization.

721255745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3509 (or 3502 counting only the distinct ones).

The product of its digits is 98000, while the sum is 38.

The square root of 721255745 is about 26856.2049627270. The cubic root of 721255745 is about 896.8017116398.

The spelling of 721255745 in words is "seven hundred twenty-one million, two hundred fifty-five thousand, seven hundred forty-five".