21380868 has 24 divisors (see below), whose sum is σ = 55432160. Its totient is φ = 7126920.

The previous prime is 21380867. The next prime is 21380881. The reversal of 21380868 is 86808312.

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

It is not an unprimeable number, because it can be changed into a prime (21380867) by changing a digit.

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, 98878 + ... + 99093.

Almost surely, 2^21380868 is an apocalyptic number.

It is an amenable number.

21380868 is an abundant number, since it is smaller than the sum of its proper divisors (34051292).

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

21380868 is a wasteful number, since it uses less digits than its factorization.

21380868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197984 (or 197976 counting only the distinct ones).

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

The square root of 21380868 is about 4623.9450688779. The cubic root of 21380868 is about 277.5503487898.

The spelling of 21380868 in words is "twenty-one million, three hundred eighty thousand, eight hundred sixty-eight".