21133880 has 32 divisors (see below), whose sum is σ = 47733840. Its totient is φ = 8421120.

The previous prime is 21133867. The next prime is 21133897. The reversal of 21133880 is 8833112.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11420 + ... + 13140.

Almost surely, 2^21133880 is an apocalyptic number.

21133880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21133880 is an abundant number, since it is smaller than the sum of its proper divisors (26599960).

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

21133880 is a wasteful number, since it uses less digits than its factorization.

21133880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2039 (or 2035 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 21133880 is about 4597.1599928652. The cubic root of 21133880 is about 276.4774693962.

Adding to 21133880 its reverse (8833112), we get a palindrome (29966992).

The spelling of 21133880 in words is "twenty-one million, one hundred thirty-three thousand, eight hundred eighty".