239870021 has 4 divisors (see below), whose sum is σ = 243248544. Its totient is φ = 236491500.

The previous prime is 239870009. The next prime is 239870027. The reversal of 239870021 is 120078932.

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 239870021 - 2²² = 235675717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 239870021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (239870027) 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, 1689155 + ... + 1689296.

It is an arithmetic number, because the mean of its divisors is an integer number (60812136).

Almost surely, 2^239870021 is an apocalyptic number.

It is an amenable number.

239870021 is a deficient number, since it is larger than the sum of its proper divisors (3378523).

239870021 is an equidigital number, since it uses as much as digits as its factorization.

239870021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3378522.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 239870021 is about 15487.7377625010. The cubic root of 239870021 is about 621.3342934391.

The spelling of 239870021 in words is "two hundred thirty-nine million, eight hundred seventy thousand, twenty-one".