2051881 has 4 divisors (see below), whose sum is σ = 2209732. Its totient is φ = 1894032.

The previous prime is 2051851. The next prime is 2051887. The reversal of 2051881 is 1881502.

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 1166400 + 885481 = 1080^2 + 941^2 .

It is a cyclic number.

It is not a de Polignac number, because 2051881 - 2¹⁵ = 2019113 is a prime.

It is a super-2 number, since 2×2051881² = 8420431276322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2051887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78906 + ... + 78931.

It is an arithmetic number, because the mean of its divisors is an integer number (552433).

2^2051881 is an apocalyptic number.

It is an amenable number.

2051881 is a deficient number, since it is larger than the sum of its proper divisors (157851).

2051881 is a wasteful number, since it uses less digits than its factorization.

2051881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157850.

The product of its (nonzero) digits is 640, while the sum is 25.

The square root of 2051881 is about 1432.4388294095. The cubic root of 2051881 is about 127.0722510328.

The spelling of 2051881 in words is "two million, fifty-one thousand, eight hundred eighty-one".