721243105 has 32 divisors (see below), whose sum is σ = 1002015360. Its totient is φ = 492549120.

The previous prime is 721243091. The next prime is 721243111. The reversal of 721243105 is 501342127.

It is a happy number.

It is not a de Polignac number, because 721243105 - 2⁹ = 721242593 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721243105.

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, 707286 + ... + 708304.

It is an arithmetic number, because the mean of its divisors is an integer number (31312980).

Almost surely, 2^721243105 is an apocalyptic number.

It is an amenable number.

721243105 is a deficient number, since it is larger than the sum of its proper divisors (280772255).

721243105 is a wasteful number, since it uses less digits than its factorization.

721243105 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1809.

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 721243105 is about 26855.9696343290. The cubic root of 721243105 is about 896.7964727954.

The spelling of 721243105 in words is "seven hundred twenty-one million, two hundred forty-three thousand, one hundred five".