213839991 has 24 divisors (see below), whose sum is σ = 327744144. Its totient is φ = 133889280.

The previous prime is 213839959. The next prime is 213839999. The reversal of 213839991 is 199938312.

It is a happy number.

It is not a de Polignac number, because 213839991 - 2⁵ = 213839959 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213839999) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 88621 + ... + 91001.

It is an arithmetic number, because the mean of its divisors is an integer number (13656006).

Almost surely, 2^213839991 is an apocalyptic number.

213839991 is a deficient number, since it is larger than the sum of its proper divisors (113904153).

213839991 is a wasteful number, since it uses less digits than its factorization.

213839991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2991 (or 2988 counting only the distinct ones).

The product of its digits is 104976, while the sum is 45.

The square root of 213839991 is about 14623.2688206160. The cubic root of 213839991 is about 597.9932876582.

The spelling of 213839991 in words is "two hundred thirteen million, eight hundred thirty-nine thousand, nine hundred ninety-one".