21242554 has 16 divisors (see below), whose sum is σ = 33823656. Its totient is φ = 9971200.

The previous prime is 21242549. The next prime is 21242563. The reversal of 21242554 is 45524212.

It can be written as a sum of positive squares in 4 ways, for example, as 11799225 + 9443329 = 3435^2 + 3073^2 .

It is a super-2 number, since 2×21242554² = 902492200885832, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25464 + ... + 26284.

Almost surely, 2^21242554 is an apocalyptic number.

21242554 is a deficient number, since it is larger than the sum of its proper divisors (12581102).

21242554 is a wasteful number, since it uses less digits than its factorization.

21242554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1601.

The product of its digits is 3200, while the sum is 25.

The square root of 21242554 is about 4608.9645257910. The cubic root of 21242554 is about 276.9505574541.

Adding to 21242554 its reverse (45524212), we get a palindrome (66766766).

The spelling of 21242554 in words is "twenty-one million, two hundred forty-two thousand, five hundred fifty-four".