21489811 has 8 divisors (see below), whose sum is σ = 24684800. Its totient is φ = 18326088.

The previous prime is 21489803. The next prime is 21489821. The reversal of 21489811 is 11898412.

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

It is a cyclic number.

It is not a de Polignac number, because 21489811 - 2³ = 21489803 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21489821) 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 7 ways as a sum of consecutive naturals, for example, 6321 + ... + 9106.

It is an arithmetic number, because the mean of its divisors is an integer number (3085600).

Almost surely, 2^21489811 is an apocalyptic number.

21489811 is a deficient number, since it is larger than the sum of its proper divisors (3194989).

21489811 is a wasteful number, since it uses less digits than its factorization.

21489811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15633.

The product of its digits is 4608, while the sum is 34.

The square root of 21489811 is about 4635.7104094195. The cubic root of 21489811 is about 278.0209557552.

The spelling of 21489811 in words is "twenty-one million, four hundred eighty-nine thousand, eight hundred eleven".