2151749 has 4 divisors (see below), whose sum is σ = 2157420. Its totient is φ = 2146080.

The previous prime is 2151703. The next prime is 2151767. The reversal of 2151749 is 9471512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1803649 + 348100 = 1343^2 + 590^2 .

It is a cyclic number.

It is not a de Polignac number, because 2151749 - 2¹⁶ = 2086213 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 (2151349) 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, 2222 + ... + 3039.

It is an arithmetic number, because the mean of its divisors is an integer number (539355).

2^2151749 is an apocalyptic number.

It is an amenable number.

2151749 is a deficient number, since it is larger than the sum of its proper divisors (5671).

2151749 is an equidigital number, since it uses as much as digits as its factorization.

2151749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5670.

The product of its digits is 2520, while the sum is 29.

The square root of 2151749 is about 1466.8841126688. The cubic root of 2151749 is about 129.1012765564.

The spelling of 2151749 in words is "two million, one hundred fifty-one thousand, seven hundred forty-nine".