21836880 has 120 divisors (see below), whose sum is σ = 79010568. Its totient is φ = 5372928.

The previous prime is 21836879. The next prime is 21836917. The reversal of 21836880 is 8863812.

21836880 is a `hidden beast` number, since 218 + 368 + 80 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 46656 + 21790224 = 216^2 + 4668^2 .

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8194 + ... + 10526.

Almost surely, 2^21836880 is an apocalyptic number.

21836880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21836880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39505284).

21836880 is an abundant number, since it is smaller than the sum of its proper divisors (57173688).

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

21836880 is a wasteful number, since it uses less digits than its factorization.

21836880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2365 (or 2356 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 21836880 is about 4672.9947571124. The cubic root of 21836880 is about 279.5096861199.

The spelling of 21836880 in words is "twenty-one million, eight hundred thirty-six thousand, eight hundred eighty".