239021991 has 12 divisors (see below), whose sum is σ = 371812168. Its totient is φ = 147090384.

The previous prime is 239021971. The next prime is 239021999. The reversal of 239021991 is 199120932.

It is a happy number.

It is not a de Polignac number, because 239021991 - 2¹⁰ = 239020967 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (239021999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1021345 + ... + 1021578.

Almost surely, 2^239021991 is an apocalyptic number.

239021991 is a deficient number, since it is larger than the sum of its proper divisors (132790177).

239021991 is a wasteful number, since it uses less digits than its factorization.

239021991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2042942 (or 2042939 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 239021991 is about 15460.3360571496. The cubic root of 239021991 is about 620.6012126892.

The spelling of 239021991 in words is "two hundred thirty-nine million, twenty-one thousand, nine hundred ninety-one".