721675139 has 2 divisors, whose sum is σ = 721675140. Its totient is φ = 721675138.

The previous prime is 721675127. The next prime is 721675147. The reversal of 721675139 is 931576127.

It is a strong prime.

It is an emirp because it is prime and its reverse (931576127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721675139 - 2⁸ = 721674883 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 721675096 and 721675105.

It is not a weakly prime, because it can be changed into another prime (721675739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360837569 + 360837570.

It is an arithmetic number, because the mean of its divisors is an integer number (360837570).

Almost surely, 2^721675139 is an apocalyptic number.

721675139 is a deficient number, since it is larger than the sum of its proper divisors (1).

721675139 is an equidigital number, since it uses as much as digits as its factorization.

721675139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 79380, while the sum is 41.

The square root of 721675139 is about 26864.0119676864. The cubic root of 721675139 is about 896.9755013035.

The spelling of 721675139 in words is "seven hundred twenty-one million, six hundred seventy-five thousand, one hundred thirty-nine".