21364266 has 64 divisors (see below), whose sum is σ = 53830656. Its totient is φ = 5491200.

The previous prime is 21364237. The next prime is 21364267. The reversal of 21364266 is 66246312.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21364267) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 60346 + ... + 60698.

It is an arithmetic number, because the mean of its divisors is an integer number (841104).

Almost surely, 2^21364266 is an apocalyptic number.

21364266 is the 2471-st nonagonal number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21364266, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26915328).

21364266 is an abundant number, since it is smaller than the sum of its proper divisors (32466390).

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

21364266 is a wasteful number, since it uses less digits than its factorization.

21364266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 507.

The product of its digits is 10368, while the sum is 30.

The square root of 21364266 is about 4622.1494999621. The cubic root of 21364266 is about 277.4784919618.

The spelling of 21364266 in words is "twenty-one million, three hundred sixty-four thousand, two hundred sixty-six".