21233506 has 16 divisors (see below), whose sum is σ = 36945216. Its totient is φ = 8963856.

The previous prime is 21233503. The next prime is 21233579. The reversal of 21233506 is 60533212.

It is not an unprimeable number, because it can be changed into a prime (21233503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10381 + ... + 12256.

It is an arithmetic number, because the mean of its divisors is an integer number (2309076).

Almost surely, 2^21233506 is an apocalyptic number.

21233506 is a deficient number, since it is larger than the sum of its proper divisors (15711710).

21233506 is a wasteful number, since it uses less digits than its factorization.

21233506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22713.

The product of its (nonzero) digits is 1080, while the sum is 22.

The square root of 21233506 is about 4607.9828558709. The cubic root of 21233506 is about 276.9112306621.

Adding to 21233506 its reverse (60533212), we get a palindrome (81766718).

The spelling of 21233506 in words is "twenty-one million, two hundred thirty-three thousand, five hundred six".