2851681 has 4 divisors (see below), whose sum is σ = 3259072. Its totient is φ = 2444292.

The previous prime is 2851661. The next prime is 2851727. The reversal of 2851681 is 1861582.

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 2851681 - 2⁹ = 2851169 is a prime.

It is a super-2 number, since 2×2851681² = 16264169051522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2851601) 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, 203685 + ... + 203698.

It is an arithmetic number, because the mean of its divisors is an integer number (814768).

2^2851681 is an apocalyptic number.

It is an amenable number.

2851681 is a deficient number, since it is larger than the sum of its proper divisors (407391).

2851681 is an equidigital number, since it uses as much as digits as its factorization.

2851681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 407390.

The product of its digits is 3840, while the sum is 31.

The square root of 2851681 is about 1688.6920974529. The cubic root of 2851681 is about 141.8078635307.

Subtracting from 2851681 its reverse (1861582), we obtain a palindrome (990099).

The spelling of 2851681 in words is "two million, eight hundred fifty-one thousand, six hundred eighty-one".