2131881 has 4 divisors (see below), whose sum is σ = 2842512. Its totient is φ = 1421252.

The previous prime is 2131867. The next prime is 2131907. The reversal of 2131881 is 1881312.

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 2131881 - 2⁵ = 2131849 is a prime.

It is a super-2 number, since 2×2131881² = 9089833196322, which contains 22 as substring.

It is an Ulam number.

It is a D-number.

2131881 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2131081) 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, 355311 + ... + 355316.

It is an arithmetic number, because the mean of its divisors is an integer number (710628).

2^2131881 is an apocalyptic number.

It is an amenable number.

2131881 is a deficient number, since it is larger than the sum of its proper divisors (710631).

2131881 is an equidigital number, since it uses as much as digits as its factorization.

2131881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 710630.

The product of its digits is 384, while the sum is 24.

The square root of 2131881 is about 1460.0962297054. The cubic root of 2131881 is about 128.7026985571.

The spelling of 2131881 in words is "two million, one hundred thirty-one thousand, eight hundred eighty-one".