2809881 has 6 divisors (see below), whose sum is σ = 4058730. Its totient is φ = 1873248.

The previous prime is 2809867. The next prime is 2809883. The reversal of 2809881 is 1889082.

It can be written as a sum of positive squares in only one way, i.e., 2752281 + 57600 = 1659^2 + 240^2 .

It is not a de Polignac number, because 2809881 - 2¹⁵ = 2777113 is a prime.

It is a super-2 number, since 2×2809881² = 15790862468322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (2809883) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 156096 + ... + 156113.

It is an arithmetic number, because the mean of its divisors is an integer number (676455).

2^2809881 is an apocalyptic number.

It is an amenable number.

2809881 is a deficient number, since it is larger than the sum of its proper divisors (1248849).

2809881 is a wasteful number, since it uses less digits than its factorization.

2809881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312215 (or 312212 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 2809881 is about 1676.2699663240. The cubic root of 2809881 is about 141.1115760875. Note that the first 3 decimals are identical.

The spelling of 2809881 in words is "two million, eight hundred nine thousand, eight hundred eighty-one".