721675138 has 16 divisors (see below), whose sum is σ = 1158804000. Its totient is φ = 336051072.

The previous prime is 721675127. The next prime is 721675139. The reversal of 721675138 is 831576127.

It is a self number, because there is not a number n which added to its sum of digits gives 721675138.

It is not an unprimeable number, because it can be changed into a prime (721675139) 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, 158703 + ... + 163186.

It is an arithmetic number, because the mean of its divisors is an integer number (72425250).

Almost surely, 2^721675138 is an apocalyptic number.

721675138 is a deficient number, since it is larger than the sum of its proper divisors (437128862).

721675138 is a wasteful number, since it uses less digits than its factorization.

721675138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321969.

The product of its digits is 70560, while the sum is 40.

The square root of 721675138 is about 26864.0119490742. The cubic root of 721675138 is about 896.9755008892.

The spelling of 721675138 in words is "seven hundred twenty-one million, six hundred seventy-five thousand, one hundred thirty-eight".