21791800 has 24 divisors (see below), whose sum is σ = 50666400. Its totient is φ = 8716640.

The previous prime is 21791797. The next prime is 21791821. The reversal of 21791800 is 819712.

It is a plaindrome in base 11.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54280 + ... + 54679.

It is an arithmetic number, because the mean of its divisors is an integer number (2111100).

Almost surely, 2^21791800 is an apocalyptic number.

21791800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21791800 is an abundant number, since it is smaller than the sum of its proper divisors (28874600).

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

21791800 is a wasteful number, since it uses less digits than its factorization.

21791800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108975 (or 108966 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 21791800 is about 4668.1688058595. The cubic root of 21791800 is about 279.3172139157.

The spelling of 21791800 in words is "twenty-one million, seven hundred ninety-one thousand, eight hundred".