2857681 has 4 divisors (see below), whose sum is σ = 2981952. Its totient is φ = 2733412.

The previous prime is 2857663. The next prime is 2857693. The reversal of 2857681 is 1867582.

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 de Polignac number, because none of the positive numbers 2^k-2857681 is a prime.

It is a super-2 number, since 2×2857681² = 16332681395522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2857681.

It is not an unprimeable number, because it can be changed into a prime (2857661) 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, 62101 + ... + 62146.

It is an arithmetic number, because the mean of its divisors is an integer number (745488).

2^2857681 is an apocalyptic number.

It is an amenable number.

2857681 is a deficient number, since it is larger than the sum of its proper divisors (124271).

2857681 is a wasteful number, since it uses less digits than its factorization.

2857681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124270.

The product of its digits is 26880, while the sum is 37.

The square root of 2857681 is about 1690.4676867660. The cubic root of 2857681 is about 141.9072494886.

Subtracting from 2857681 its reverse (1867582), we obtain a palindrome (990099).

The spelling of 2857681 in words is "two million, eight hundred fifty-seven thousand, six hundred eighty-one".