21437125 has 16 divisors (see below), whose sum is σ = 26887536. Its totient is φ = 17064000.

The previous prime is 21437113. The next prime is 21437147. The reversal of 21437125 is 52173412.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 13786369 + 7650756 = 3713^2 + 2766^2 .

It is not a de Polignac number, because 21437125 - 2¹¹ = 21435077 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

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 21437125.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39355 + ... + 39895.

It is an arithmetic number, because the mean of its divisors is an integer number (1680471).

Almost surely, 2^21437125 is an apocalyptic number.

21437125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21437125 is a deficient number, since it is larger than the sum of its proper divisors (5450411).

21437125 is an equidigital number, since it uses as much as digits as its factorization.

21437125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 873 (or 863 counting only the distinct ones).

The product of its digits is 1680, while the sum is 25.

The square root of 21437125 is about 4630.0242979924. The cubic root of 21437125 is about 277.7935642880.

The spelling of 21437125 in words is "twenty-one million, four hundred thirty-seven thousand, one hundred twenty-five".