231872381 has 4 divisors (see below), whose sum is σ = 249708732. Its totient is φ = 214036032.

The previous prime is 231872357. The next prime is 231872393. The reversal of 231872381 is 183278132.

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 120253156 + 111619225 = 10966^2 + 10565^2 .

It is a cyclic number.

It is not a de Polignac number, because 231872381 - 2¹⁸ = 231610237 is a prime.

It is a super-2 number, since 2×231872381² = 107529602141218322, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231872341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8918156 + ... + 8918181.

It is an arithmetic number, because the mean of its divisors is an integer number (62427183).

Almost surely, 2^231872381 is an apocalyptic number.

It is an amenable number.

231872381 is a deficient number, since it is larger than the sum of its proper divisors (17836351).

231872381 is a wasteful number, since it uses less digits than its factorization.

231872381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17836350.

The product of its digits is 16128, while the sum is 35.

The square root of 231872381 is about 15227.3563365412. The cubic root of 231872381 is about 614.3506760808.

The spelling of 231872381 in words is "two hundred thirty-one million, eight hundred seventy-two thousand, three hundred eighty-one".