21367866 has 32 divisors (see below), whose sum is σ = 47513088. Its totient is φ = 6361920.

The previous prime is 21367831. The next prime is 21367883. The reversal of 21367866 is 66876312.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2001 + ... + 6836.

It is an arithmetic number, because the mean of its divisors is an integer number (1484784).

Almost surely, 2^21367866 is an apocalyptic number.

21367866 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21367866 is an abundant number, since it is smaller than the sum of its proper divisors (26145222).

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

21367866 is a wasteful number, since it uses less digits than its factorization.

21367866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8886.

The product of its digits is 72576, while the sum is 39.

The square root of 21367866 is about 4622.5389127621. The cubic root of 21367866 is about 277.4940766530.

The spelling of 21367866 in words is "twenty-one million, three hundred sixty-seven thousand, eight hundred sixty-six".