2143681 has 4 divisors (see below), whose sum is σ = 2212864. Its totient is φ = 2074500.

The previous prime is 2143667. The next prime is 2143711. The reversal of 2143681 is 1863412.

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 a de Polignac number, because none of the positive numbers 2^k-2143681 is a prime.

It is a super-2 number, since 2×2143681² = 9190736459522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2143621) 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, 34545 + ... + 34606.

It is an arithmetic number, because the mean of its divisors is an integer number (553216).

2^2143681 is an apocalyptic number.

It is an amenable number.

2143681 is a deficient number, since it is larger than the sum of its proper divisors (69183).

2143681 is an equidigital number, since it uses as much as digits as its factorization.

2143681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69182.

The product of its digits is 1152, while the sum is 25.

The square root of 2143681 is about 1464.1314831667. The cubic root of 2143681 is about 128.9397190462.

It can be divided in two parts, 214368 and 1, that added together give a square (214369 = 463²).

The spelling of 2143681 in words is "two million, one hundred forty-three thousand, six hundred eighty-one".