721662105 has 32 divisors (see below), whose sum is σ = 1174238208. Its totient is φ = 378392000.

The previous prime is 721662103. The next prime is 721662167. The reversal of 721662105 is 501266127.

It is not a de Polignac number, because 721662105 - 2¹ = 721662103 is a prime.

It is not an unprimeable number, because it can be changed into a prime (721662103) 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 31 ways as a sum of consecutive naturals, for example, 496630 + ... + 498080.

It is an arithmetic number, because the mean of its divisors is an integer number (36694944).

Almost surely, 2^721662105 is an apocalyptic number.

It is an amenable number.

721662105 is a deficient number, since it is larger than the sum of its proper divisors (452576103).

721662105 is a wasteful number, since it uses less digits than its factorization.

721662105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1997.

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 721662105 is about 26863.7693743823. The cubic root of 721662105 is about 896.9701012518.

The spelling of 721662105 in words is "seven hundred twenty-one million, six hundred sixty-two thousand, one hundred five".