21675425 has 12 divisors (see below), whose sum is σ = 28459116. Its totient is φ = 16320000.

The previous prime is 21675419. The next prime is 21675427. The reversal of 21675425 is 52457612.

It can be written as a sum of positive squares in 6 ways, for example, as 625681 + 21049744 = 791^2 + 4588^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21675425 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21675391 and 21675400.

It is not an unprimeable number, because it can be changed into a prime (21675427) 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 11 ways as a sum of consecutive naturals, for example, 25076 + ... + 25925.

It is an arithmetic number, because the mean of its divisors is an integer number (2371593).

Almost surely, 2^21675425 is an apocalyptic number.

21675425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21675425 is a deficient number, since it is larger than the sum of its proper divisors (6783691).

21675425 is a wasteful number, since it uses less digits than its factorization.

21675425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51028 (or 51023 counting only the distinct ones).

The product of its digits is 16800, while the sum is 32.

The square root of 21675425 is about 4655.6873821166. The cubic root of 21675425 is about 278.8191125459.

The spelling of 21675425 in words is "twenty-one million, six hundred seventy-five thousand, four hundred twenty-five".