21808850 has 24 divisors (see below), whose sum is σ = 46360128. Its totient is φ = 7477200.

The previous prime is 21808837. The next prime is 21808859. The reversal of 21808850 is 5880812.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21808859) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 30806 + ... + 31505.

It is an arithmetic number, because the mean of its divisors is an integer number (1931672).

Almost surely, 2^21808850 is an apocalyptic number.

21808850 is an abundant number, since it is smaller than the sum of its proper divisors (24551278).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21808850 is a wasteful number, since it uses less digits than its factorization.

21808850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62330 (or 62325 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 32.

The square root of 21808850 is about 4669.9946466779. The cubic root of 21808850 is about 279.3900412637.

The spelling of 21808850 in words is "twenty-one million, eight hundred eight thousand, eight hundred fifty".