231199921 has 4 divisors (see below), whose sum is σ = 233246052. Its totient is φ = 229153792.

The previous prime is 231199897. The next prime is 231199973. The reversal of 231199921 is 129991132.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 50566321 + 180633600 = 7111^2 + 13440^2 .

It is a cyclic number.

It is not a de Polignac number, because 231199921 - 2⁵ = 231199889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (231199981) 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, 1022896 + ... + 1023121.

It is an arithmetic number, because the mean of its divisors is an integer number (58311513).

Almost surely, 2^231199921 is an apocalyptic number.

It is an amenable number.

231199921 is a deficient number, since it is larger than the sum of its proper divisors (2046131).

231199921 is a wasteful number, since it uses less digits than its factorization.

231199921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2046130.

The product of its digits is 8748, while the sum is 37.

The square root of 231199921 is about 15205.2596492135. The cubic root of 231199921 is about 613.7562021266.

The spelling of 231199921 in words is "two hundred thirty-one million, one hundred ninety-nine thousand, nine hundred twenty-one".