21222475 has 12 divisors (see below), whose sum is σ = 26488384. Its totient is φ = 16866720.

The previous prime is 21222469. The next prime is 21222479. The reversal of 21222475 is 57422212.

It is not a de Polignac number, because 21222475 - 2⁷ = 21222347 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21222479) 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, 1222 + ... + 6628.

Almost surely, 2^21222475 is an apocalyptic number.

21222475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21222475 is a deficient number, since it is larger than the sum of its proper divisors (5265909).

21222475 is a wasteful number, since it uses less digits than its factorization.

21222475 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5574 (or 5569 counting only the distinct ones).

The product of its digits is 2240, while the sum is 25.

The square root of 21222475 is about 4606.7857558172. The cubic root of 21222475 is about 276.8632697193.

Adding to 21222475 its reverse (57422212), we get a palindrome (78644687).

The spelling of 21222475 in words is "twenty-one million, two hundred twenty-two thousand, four hundred seventy-five".