2861681 has 4 divisors (see below), whose sum is σ = 2866752. Its totient is φ = 2856612.

The previous prime is 2861671. The next prime is 2861699. The reversal of 2861681 is 1861682.

2861681 is nontrivially palindromic in base 9.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1861682 = 2 ⋅930841.

It is a cyclic number.

It is not a de Polignac number, because 2861681 - 2¹⁰ = 2860657 is a prime.

It is a super-2 number, since 2×2861681² = 16378436291522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2861671) 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, 1565 + ... + 2858.

It is an arithmetic number, because the mean of its divisors is an integer number (716688).

2^2861681 is an apocalyptic number.

It is an amenable number.

2861681 is a deficient number, since it is larger than the sum of its proper divisors (5071).

2861681 is an equidigital number, since it uses as much as digits as its factorization.

2861681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5070.

The product of its digits is 4608, while the sum is 32.

The square root of 2861681 is about 1691.6503775899. The cubic root of 2861681 is about 141.9734295323.

Subtracting from 2861681 its reverse (1861682), we obtain a palindrome (999999).

The spelling of 2861681 in words is "two million, eight hundred sixty-one thousand, six hundred eighty-one".