139258021 has 4 divisors (see below), whose sum is σ = 159152032. Its totient is φ = 119364012.

The previous prime is 139258019. The next prime is 139258043. The reversal of 139258021 is 120852931.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 139258021 - 2¹ = 139258019 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 (139258001) 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, 9946995 + ... + 9947008.

It is an arithmetic number, because the mean of its divisors is an integer number (39788008).

Almost surely, 2^139258021 is an apocalyptic number.

It is an amenable number.

139258021 is a deficient number, since it is larger than the sum of its proper divisors (19894011).

139258021 is an equidigital number, since it uses as much as digits as its factorization.

139258021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19894010.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 139258021 is about 11800.7635769894. The cubic root of 139258021 is about 518.3304701912.

The spelling of 139258021 in words is "one hundred thirty-nine million, two hundred fifty-eight thousand, twenty-one".