21225275 has 12 divisors (see below), whose sum is σ = 26524344. Its totient is φ = 16848000.

The previous prime is 21225263. The next prime is 21225277. The reversal of 21225275 is 57252212.

It is not a de Polignac number, because 21225275 - 2²⁰ = 20176699 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21225277) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35 + ... + 6515.

It is an arithmetic number, because the mean of its divisors is an integer number (2210362).

Almost surely, 2^21225275 is an apocalyptic number.

21225275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21225275 is a deficient number, since it is larger than the sum of its proper divisors (5299069).

21225275 is a wasteful number, since it uses less digits than its factorization.

21225275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6622 (or 6617 counting only the distinct ones).

The product of its digits is 2800, while the sum is 26.

The square root of 21225275 is about 4607.0896453184. The cubic root of 21225275 is about 276.8754452245.

Adding to 21225275 its reverse (57252212), we get a palindrome (78477487).

The spelling of 21225275 in words is "twenty-one million, two hundred twenty-five thousand, two hundred seventy-five".