21266646 has 8 divisors (see below), whose sum is σ = 42533304. Its totient is φ = 7088880.

The previous prime is 21266633. The next prime is 21266669. The reversal of 21266646 is 64666212.

It is a sphenic number, since it is the product of 3 distinct primes.

21266646 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1772215 + ... + 1772226.

It is an arithmetic number, because the mean of its divisors is an integer number (5316663).

Almost surely, 2^21266646 is an apocalyptic number.

21266646 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21266646 is a wasteful number, since it uses less digits than its factorization.

21266646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3544446.

The product of its digits is 20736, while the sum is 33.

The square root of 21266646 is about 4611.5773874023. The cubic root of 21266646 is about 277.0552180014.

It can be divided in two parts, 21266 and 646, that added together give a palindrome (21912).

The spelling of 21266646 in words is "twenty-one million, two hundred sixty-six thousand, six hundred forty-six".