18721125 has 60 divisors (see below), whose sum is σ = 35732268. Its totient is φ = 9752400.

The previous prime is 18721123. The next prime is 18721127. The reversal of 18721125 is 52112781.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It is an interprime number because it is at equal distance from previous prime (18721123) and next prime (18721127).

It can be written as a sum of positive squares in 2 ways, for example, as 599076 + 18122049 = 774^2 + 4257^2 .

It is not a de Polignac number, because 18721125 - 2¹ = 18721123 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18721123) by changing a digit.

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 59 ways as a sum of consecutive naturals, for example, 435354 + ... + 435396.

Almost surely, 2^18721125 is an apocalyptic number.

18721125 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18721125 is a deficient number, since it is larger than the sum of its proper divisors (17011143).

18721125 is an frugal number, since it uses more digits than its factorization.

18721125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113 (or 51 counting only the distinct ones).

The product of its digits is 1120, while the sum is 27.

The square root of 18721125 is about 4326.7915364621. The cubic root of 18721125 is about 265.5281977137.

It can be divided in two parts, 187 and 21125, that added together give a palindrome (21312).

The spelling of 18721125 in words is "eighteen million, seven hundred twenty-one thousand, one hundred twenty-five".