139321591 has 4 divisors (see below), whose sum is σ = 142561672. Its totient is φ = 136081512.

The previous prime is 139321561. The next prime is 139321601. The reversal of 139321591 is 195123931.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 139321591 - 2⁷ = 139321463 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139321531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1619976 + ... + 1620061.

It is an arithmetic number, because the mean of its divisors is an integer number (35640418).

Almost surely, 2^139321591 is an apocalyptic number.

139321591 is a deficient number, since it is larger than the sum of its proper divisors (3240081).

139321591 is an equidigital number, since it uses as much as digits as its factorization.

139321591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3240080.

The product of its digits is 7290, while the sum is 34.

The square root of 139321591 is about 11803.4567394471. The cubic root of 139321591 is about 518.4093292165.

The spelling of 139321591 in words is "one hundred thirty-nine million, three hundred twenty-one thousand, five hundred ninety-one".