21552418 has 8 divisors (see below), whose sum is σ = 32692140. Its totient is φ = 10655040.

The previous prime is 21552383. The next prime is 21552437. The reversal of 21552418 is 81425512.

It can be written as a sum of positive squares in 2 ways, for example, as 20223009 + 1329409 = 4497^2 + 1153^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60363 + ... + 60718.

Almost surely, 2^21552418 is an apocalyptic number.

21552418 is a deficient number, since it is larger than the sum of its proper divisors (11139722).

21552418 is a wasteful number, since it uses less digits than its factorization.

21552418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121172.

The product of its digits is 3200, while the sum is 28.

The square root of 21552418 is about 4642.4581850567. The cubic root of 21552418 is about 278.2906833028.

The spelling of 21552418 in words is "twenty-one million, five hundred fifty-two thousand, four hundred eighteen".