21552730 has 8 divisors (see below), whose sum is σ = 38794932. Its totient is φ = 8621088.

The previous prime is 21552709. The next prime is 21552731. The reversal of 21552730 is 3725512.

It can be written as a sum of positive squares in 2 ways, for example, as 20693401 + 859329 = 4549^2 + 927^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21552695 and 21552704.

It is not an unprimeable number, because it can be changed into a prime (21552731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1077627 + ... + 1077646.

Almost surely, 2^21552730 is an apocalyptic number.

21552730 is a deficient number, since it is larger than the sum of its proper divisors (17242202).

21552730 is a wasteful number, since it uses less digits than its factorization.

21552730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2155280.

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 21552730 is about 4642.4917878226. The cubic root of 21552730 is about 278.2920261726.

The spelling of 21552730 in words is "twenty-one million, five hundred fifty-two thousand, seven hundred thirty".