21224137209 has 8 divisors (see below), whose sum is σ = 30871472352. Its totient is φ = 12863113440.

The previous prime is 21224137163. The next prime is 21224137213. The reversal of 21224137209 is 90273142212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21224137209 - 2⁸ = 21224136953 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 643155673 = 21224137209 / (2 + 1 + 2 + 2 + 4 + 1 + 3 + 7 + 2 + 0 + 9).

It is a self number, because there is not a number n which added to its sum of digits gives 21224137209.

It is not an unprimeable number, because it can be changed into a prime (21224137279) 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, 321577804 + ... + 321577869.

It is an arithmetic number, because the mean of its divisors is an integer number (3858934044).

Almost surely, 2^21224137209 is an apocalyptic number.

It is an amenable number.

21224137209 is a deficient number, since it is larger than the sum of its proper divisors (9647335143).

21224137209 is a wasteful number, since it uses less digits than its factorization.

21224137209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 643155687.

The product of its (nonzero) digits is 12096, while the sum is 33.

The spelling of 21224137209 in words is "twenty-one billion, two hundred twenty-four million, one hundred thirty-seven thousand, two hundred nine".