18525421 has 4 divisors (see below), whose sum is σ = 18760000. Its totient is φ = 18290844.

The previous prime is 18525407. The next prime is 18525431. The reversal of 18525421 is 12452581.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12452581 = 19 ⋅655399.

It is a cyclic number.

It is not a de Polignac number, because 18525421 - 2⁷ = 18525293 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18525421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18525401) 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, 117171 + ... + 117328.

It is an arithmetic number, because the mean of its divisors is an integer number (4690000).

Almost surely, 2^18525421 is an apocalyptic number.

It is an amenable number.

18525421 is a deficient number, since it is larger than the sum of its proper divisors (234579).

18525421 is an equidigital number, since it uses as much as digits as its factorization.

18525421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234578.

The product of its digits is 3200, while the sum is 28.

The square root of 18525421 is about 4304.1167502753. The cubic root of 18525421 is about 264.5997089306.

The spelling of 18525421 in words is "eighteen million, five hundred twenty-five thousand, four hundred twenty-one".