21964189 has 4 divisors (see below), whose sum is σ = 23653756. Its totient is φ = 20274624.

The previous prime is 21964183. The next prime is 21964193. The reversal of 21964189 is 98146912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1416100 + 20548089 = 1190^2 + 4533^2 .

It is a cyclic number.

It is not a de Polignac number, because 21964189 - 2⁵ = 21964157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21964183) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 844764 + ... + 844789.

It is an arithmetic number, because the mean of its divisors is an integer number (5913439).

Almost surely, 2^21964189 is an apocalyptic number.

It is an amenable number.

21964189 is a deficient number, since it is larger than the sum of its proper divisors (1689567).

21964189 is a wasteful number, since it uses less digits than its factorization.

21964189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1689566.

The product of its digits is 31104, while the sum is 40.

The square root of 21964189 is about 4686.5967396395. The cubic root of 21964189 is about 280.0518143907.

The spelling of 21964189 in words is "twenty-one million, nine hundred sixty-four thousand, one hundred eighty-nine".