2181749 has 4 divisors (see below), whose sum is σ = 2252160. Its totient is φ = 2111340.

The previous prime is 2181737. The next prime is 2181833. The reversal of 2181749 is 9471812.

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 2181749 - 2¹² = 2177653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2181709) 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, 35159 + ... + 35220.

It is an arithmetic number, because the mean of its divisors is an integer number (563040).

2^2181749 is an apocalyptic number.

It is an amenable number.

2181749 is a deficient number, since it is larger than the sum of its proper divisors (70411).

2181749 is an equidigital number, since it uses as much as digits as its factorization.

2181749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70410.

The product of its digits is 4032, while the sum is 32.

The square root of 2181749 is about 1477.0744734102. The cubic root of 2181749 is about 129.6984925796.

The spelling of 2181749 in words is "two million, one hundred eighty-one thousand, seven hundred forty-nine".