1861749 has 12 divisors (see below), whose sum is σ = 2702700. Its totient is φ = 1234944.

The previous prime is 1861747. The next prime is 1861751. The reversal of 1861749 is 9471681.

It is an interprime number because it is at equal distance from previous prime (1861747) and next prime (1861751).

It can be written as a sum of positive squares in 2 ways, for example, as 378225 + 1483524 = 615^2 + 1218^2 .

It is not a de Polignac number, because 1861749 - 2¹ = 1861747 is a prime.

It is a super-2 number, since 2×1861749² = 6932218678002, which contains 22 as substring.

1861749 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861747) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2037 + ... + 2805.

It is an arithmetic number, because the mean of its divisors is an integer number (225225).

2^1861749 is an apocalyptic number.

It is an amenable number.

1861749 is a deficient number, since it is larger than the sum of its proper divisors (840951).

1861749 is a wasteful number, since it uses less digits than its factorization.

1861749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1044 (or 1041 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 1861749 is about 1364.4592335427. The cubic root of 1861749 is about 123.0194298078.

The spelling of 1861749 in words is "one million, eight hundred sixty-one thousand, seven hundred forty-nine".