21943386 has 48 divisors (see below), whose sum is σ = 49786464. Its totient is φ = 7243344.

The previous prime is 21943351. The next prime is 21943387. The reversal of 21943386 is 68334912.

21943386 is a `hidden beast` number, since 219 + 433 + 8 + 6 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 21943386.

It is not an unprimeable number, because it can be changed into a prime (21943387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 79080 + ... + 79356.

It is an arithmetic number, because the mean of its divisors is an integer number (1037218).

Almost surely, 2^21943386 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21943386, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24893232).

21943386 is an abundant number, since it is smaller than the sum of its proper divisors (27843078).

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

21943386 is a wasteful number, since it uses less digits than its factorization.

21943386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 457 (or 445 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 21943386 is about 4684.3767995327. The cubic root of 21943386 is about 279.9633710588.

The spelling of 21943386 in words is "twenty-one million, nine hundred forty-three thousand, three hundred eighty-six".