21226525 has 6 divisors (see below), whose sum is σ = 26320922. Its totient is φ = 16981200.

The previous prime is 21226519. The next prime is 21226531. The reversal of 21226525 is 52562212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21226519) and next prime (21226531).

It can be written as a sum of positive squares in 3 ways, for example, as 2442969 + 18783556 = 1563^2 + 4334^2 .

It is not a de Polignac number, because 21226525 - 2¹³ = 21218333 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: 849061 = 21226525 / (2 + 1 + 2 + 2 + 6 + 5 + 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 21226525.

It is a congruent 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, 424506 + ... + 424555.

Almost surely, 2^21226525 is an apocalyptic number.

21226525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21226525 is a deficient number, since it is larger than the sum of its proper divisors (5094397).

21226525 is an equidigital number, since it uses as much as digits as its factorization.

21226525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 849071 (or 849066 counting only the distinct ones).

The product of its digits is 2400, while the sum is 25.

The square root of 21226525 is about 4607.2253038027. The cubic root of 21226525 is about 276.8808803722.

Adding to 21226525 its reverse (52562212), we get a palindrome (73788737).

The spelling of 21226525 in words is "twenty-one million, two hundred twenty-six thousand, five hundred twenty-five".