21782736 has 40 divisors (see below), whose sum is σ = 62525760. Its totient is φ = 7260768.

The previous prime is 21782731. The next prime is 21782737. The reversal of 21782736 is 63728712.

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

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 21782736.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21782731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24780 + ... + 25643.

It is an arithmetic number, because the mean of its divisors is an integer number (1563144).

Almost surely, 2^21782736 is an apocalyptic number.

It is an amenable number.

21782736 is an abundant number, since it is smaller than the sum of its proper divisors (40743024).

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

21782736 is a wasteful number, since it uses less digits than its factorization.

21782736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50440 (or 50428 counting only the distinct ones).

The product of its digits is 28224, while the sum is 36.

The square root of 21782736 is about 4667.1978745281. The cubic root of 21782736 is about 279.2784824919.

The spelling of 21782736 in words is "twenty-one million, seven hundred eighty-two thousand, seven hundred thirty-six".