21465925 has 18 divisors (see below), whose sum is σ = 28777238. Its totient is φ = 15790080.

The previous prime is 21465907. The next prime is 21465937. The reversal of 21465925 is 52956412.

It is a happy number.

21465925 is nontrivially palindromic in base 4.

It can be written as a sum of positive squares in 9 ways, for example, as 103041 + 21362884 = 321^2 + 4622^2 .

It is not a de Polignac number, because 21465925 - 2²¹ = 19368773 is a prime.

It is a super-2 number, since 2×21465925² = 921571872211250, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 83397 + ... + 83653.

Almost surely, 2^21465925 is an apocalyptic number.

21465925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21465925 is a deficient number, since it is larger than the sum of its proper divisors (7311313).

21465925 is an equidigital number, since it uses as much as digits as its factorization.

21465925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 537 (or 275 counting only the distinct ones).

The product of its digits is 21600, while the sum is 34.

The square root of 21465925 is about 4633.1333889712. The cubic root of 21465925 is about 277.9179104795.

The spelling of 21465925 in words is "twenty-one million, four hundred sixty-five thousand, nine hundred twenty-five".