21365425 has 6 divisors (see below), whose sum is σ = 26493158. Its totient is φ = 17092320.

The previous prime is 21365423. The next prime is 21365441. The reversal of 21365425 is 52456312.

It can be written as a sum of positive squares in 3 ways, for example, as 7054336 + 14311089 = 2656^2 + 3783^2 .

It is not a de Polignac number, because 21365425 - 2¹ = 21365423 is a prime.

It is a super-3 number, since 3×21365425³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21365393 and 21365402.

It is not an unprimeable number, because it can be changed into a prime (21365423) 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, 427284 + ... + 427333.

Almost surely, 2^21365425 is an apocalyptic number.

21365425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21365425 is a deficient number, since it is larger than the sum of its proper divisors (5127733).

21365425 is an equidigital number, since it uses as much as digits as its factorization.

21365425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 854627 (or 854622 counting only the distinct ones).

The product of its digits is 7200, while the sum is 28.

The square root of 21365425 is about 4622.2748728305. The cubic root of 21365425 is about 277.4835095576.

The spelling of 21365425 in words is "twenty-one million, three hundred sixty-five thousand, four hundred twenty-five".