21995425 has 6 divisors (see below), whose sum is σ = 27274358. Its totient is φ = 17596320.

The previous prime is 21995423. The next prime is 21995431. The reversal of 21995425 is 52459912.

It can be written as a sum of positive squares in 3 ways, for example, as 6574096 + 15421329 = 2564^2 + 3927^2 .

It is not a de Polignac number, because 21995425 - 2¹ = 21995423 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21995423) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 439884 + ... + 439933.

Almost surely, 2^21995425 is an apocalyptic number.

21995425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21995425 is a deficient number, since it is larger than the sum of its proper divisors (5278933).

21995425 is an equidigital number, since it uses as much as digits as its factorization.

21995425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 879827 (or 879822 counting only the distinct ones).

The product of its digits is 32400, while the sum is 37.

The square root of 21995425 is about 4689.9280378274. The cubic root of 21995425 is about 280.1845084918.

The spelling of 21995425 in words is "twenty-one million, nine hundred ninety-five thousand, four hundred twenty-five".