21869880 has 64 divisors (see below), whose sum is σ = 67737600. Its totient is φ = 5642880.

The previous prime is 21869879. The next prime is 21869951. The reversal of 21869880 is 8896812.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 781 + ... + 6659.

It is an arithmetic number, because the mean of its divisors is an integer number (1058400).

Almost surely, 2^21869880 is an apocalyptic number.

21869880 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 21869880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33868800).

21869880 is an abundant number, since it is smaller than the sum of its proper divisors (45867720).

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

21869880 is a wasteful number, since it uses less digits than its factorization.

21869880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5924 (or 5920 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 42.

The square root of 21869880 is about 4676.5243504124. The cubic root of 21869880 is about 279.6504140563.

The spelling of 21869880 in words is "twenty-one million, eight hundred sixty-nine thousand, eight hundred eighty".