721318945 has 32 divisors (see below), whose sum is σ = 942480000. Its totient is φ = 528145920.

The previous prime is 721318921. The next prime is 721318951. The reversal of 721318945 is 549813127.

It is a de Polignac number, because none of the positive numbers 2^k-721318945 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 721318898 and 721318907.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 423706 + ... + 425404.

It is an arithmetic number, because the mean of its divisors is an integer number (29452500).

Almost surely, 2^721318945 is an apocalyptic number.

It is an amenable number.

721318945 is a deficient number, since it is larger than the sum of its proper divisors (221161055).

721318945 is a wasteful number, since it uses less digits than its factorization.

721318945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1873.

The product of its digits is 60480, while the sum is 40.

The square root of 721318945 is about 26857.3815737871. The cubic root of 721318945 is about 896.8279049437.

The spelling of 721318945 in words is "seven hundred twenty-one million, three hundred eighteen thousand, nine hundred forty-five".