18440253 has 18 divisors (see below), whose sum is σ = 28757274. Its totient is φ = 11319264.

The previous prime is 18440251. The next prime is 18440263. The reversal of 18440253 is 35204481.

It can be written as a sum of positive squares in 3 ways, for example, as 2424249 + 16016004 = 1557^2 + 4002^2 .

It is not a de Polignac number, because 18440253 - 2¹ = 18440251 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18440251) 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 17 ways as a sum of consecutive naturals, for example, 46251 + ... + 46647.

Almost surely, 2^18440253 is an apocalyptic number.

18440253 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

18440253 is a deficient number, since it is larger than the sum of its proper divisors (10317021).

18440253 is an equidigital number, since it uses as much as digits as its factorization.

18440253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 813 (or 413 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 18440253 is about 4294.2115690776. The cubic root of 18440253 is about 264.1935993841.

The spelling of 18440253 in words is "eighteen million, four hundred forty thousand, two hundred fifty-three".