21753425 has 6 divisors (see below), whose sum is σ = 26974278. Its totient is φ = 17402720.

The previous prime is 21753419. The next prime is 21753533. The reversal of 21753425 is 52435712.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 529 + 21752896 = 23^2 + 4664^2 .

It is not a de Polignac number, because 21753425 - 2⁴ = 21753409 is a prime.

It is a super-2 number, since 2×21753425² = 946422998461250, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 435044 + ... + 435093.

It is an arithmetic number, because the mean of its divisors is an integer number (4495713).

Almost surely, 2^21753425 is an apocalyptic number.

21753425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21753425 is a deficient number, since it is larger than the sum of its proper divisors (5220853).

21753425 is an equidigital number, since it uses as much as digits as its factorization.

21753425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 870147 (or 870142 counting only the distinct ones).

The product of its digits is 8400, while the sum is 29.

The square root of 21753425 is about 4664.0567106329. The cubic root of 21753425 is about 279.1531599119.

The spelling of 21753425 in words is "twenty-one million, seven hundred fifty-three thousand, four hundred twenty-five".