21326425 has 6 divisors (see below), whose sum is σ = 26444798. Its totient is φ = 17061120.

The previous prime is 21326413. The next prime is 21326429. The reversal of 21326425 is 52462312.

It can be written as a sum of positive squares in 3 ways, for example, as 46656 + 21279769 = 216^2 + 4613^2 .

It is not a de Polignac number, because 21326425 - 2¹⁹ = 20802137 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25), and also a Moran number because the ratio is a prime number: 853057 = 21326425 / (2 + 1 + 3 + 2 + 6 + 4 + 2 + 5).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21326425.

It is not an unprimeable number, because it can be changed into a prime (21326429) 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, 426504 + ... + 426553.

Almost surely, 2^21326425 is an apocalyptic number.

21326425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21326425 is a deficient number, since it is larger than the sum of its proper divisors (5118373).

21326425 is an equidigital number, since it uses as much as digits as its factorization.

21326425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 853067 (or 853062 counting only the distinct ones).

The product of its digits is 2880, while the sum is 25.

The square root of 21326425 is about 4618.0542439430. The cubic root of 21326425 is about 277.3145691906.

Adding to 21326425 its reverse (52462312), we get a palindrome (73788737).

The spelling of 21326425 in words is "twenty-one million, three hundred twenty-six thousand, four hundred twenty-five".