21244806 has 48 divisors (see below), whose sum is σ = 51459408. Its totient is φ = 6278400.

The previous prime is 21244787. The next prime is 21244807. The reversal of 21244806 is 60844212.

21244806 is a `hidden beast` number, since 212 + 448 + 0 + 6 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21244806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21244807) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6810 + ... + 9426.

It is an arithmetic number, because the mean of its divisors is an integer number (1072071).

Almost surely, 2^21244806 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21244806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25729704).

21244806 is an abundant number, since it is smaller than the sum of its proper divisors (30214602).

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

21244806 is a wasteful number, since it uses less digits than its factorization.

21244806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2677 (or 2674 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 21244806 is about 4609.2088258182. The cubic root of 21244806 is about 276.9603439518.

The spelling of 21244806 in words is "twenty-one million, two hundred forty-four thousand, eight hundred six".