21964218 has 16 divisors (see below), whose sum is σ = 45838656. Its totient is φ = 7003040.

The previous prime is 21964193. The next prime is 21964219. The reversal of 21964218 is 81246912.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21964219) 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, 79443 + ... + 79718.

It is an arithmetic number, because the mean of its divisors is an integer number (2864916).

Almost surely, 2^21964218 is an apocalyptic number.

21964218 is an abundant number, since it is smaller than the sum of its proper divisors (23874438).

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

21964218 is a wasteful number, since it uses less digits than its factorization.

21964218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159189.

The product of its digits is 6912, while the sum is 33.

The square root of 21964218 is about 4686.5998335680. The cubic root of 21964218 is about 280.0519376443.

The spelling of 21964218 in words is "twenty-one million, nine hundred sixty-four thousand, two hundred eighteen".