21284275 has 12 divisors (see below), whose sum is σ = 27782200. Its totient is φ = 16130880.

The previous prime is 21284273. The next prime is 21284281. The reversal of 21284275 is 57248212.

It is a happy number.

It is not a de Polignac number, because 21284275 - 2¹ = 21284273 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21284273) 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, 21930 + ... + 22879.

Almost surely, 2^21284275 is an apocalyptic number.

21284275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21284275 is a deficient number, since it is larger than the sum of its proper divisors (6497925).

21284275 is a wasteful number, since it uses less digits than its factorization.

21284275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44838 (or 44833 counting only the distinct ones).

The product of its digits is 8960, while the sum is 31.

The square root of 21284275 is about 4613.4883764891. The cubic root of 21284275 is about 277.1317518919.

The spelling of 21284275 in words is "twenty-one million, two hundred eighty-four thousand, two hundred seventy-five".