18921325 has 6 divisors (see below), whose sum is σ = 23462474. Its totient is φ = 15137040.

The previous prime is 18921317. The next prime is 18921337. The reversal of 18921325 is 52312981.

It can be written as a sum of positive squares in 3 ways, for example, as 1798281 + 17123044 = 1341^2 + 4138^2 .

It is not a de Polignac number, because 18921325 - 2³ = 18921317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 378402 + ... + 378451.

Almost surely, 2^18921325 is an apocalyptic number.

It is an amenable number.

18921325 is a deficient number, since it is larger than the sum of its proper divisors (4541149).

18921325 is an equidigital number, since it uses as much as digits as its factorization.

18921325 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 756863 (or 756858 counting only the distinct ones).

The product of its digits is 4320, while the sum is 31.

The square root of 18921325 is about 4349.8649404321. The cubic root of 18921325 is about 266.4713456866.

The spelling of 18921325 in words is "eighteen million, nine hundred twenty-one thousand, three hundred twenty-five".