1861449253 has 4 divisors (see below), whose sum is σ = 1861538380. Its totient is φ = 1861360128.

The previous prime is 1861449223. The next prime is 1861449283. The reversal of 1861449253 is 3529441681.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 3529441681 = 173 ⋅20401397.

It is an interprime number because it is at equal distance from previous prime (1861449223) and next prime (1861449283).

It can be written as a sum of positive squares in 2 ways, for example, as 1069420804 + 792028449 = 32702^2 + 28143^2 .

It is a cyclic number.

It is not a de Polignac number, because 1861449253 - 2⁹ = 1861448741 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 (1861449203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5551 + ... + 61267.

It is an arithmetic number, because the mean of its divisors is an integer number (465384595).

Almost surely, 2^1861449253 is an apocalyptic number.

It is an amenable number.

1861449253 is a deficient number, since it is larger than the sum of its proper divisors (89127).

1861449253 is an equidigital number, since it uses as much as digits as its factorization.

1861449253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89126.

The product of its digits is 207360, while the sum is 43.

The square root of 1861449253 is about 43144.5159087456. The cubic root of 1861449253 is about 1230.1282729158.

The spelling of 1861449253 in words is "one billion, eight hundred sixty-one million, four hundred forty-nine thousand, two hundred fifty-three".