22709821 has 4 divisors (see below), whose sum is σ = 22762944. Its totient is φ = 22656700.

The previous prime is 22709803. The next prime is 22709831. The reversal of 22709821 is 12890722.

It is the 1946-th star number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-22709821 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22709831) 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 3 ways as a sum of consecutive naturals, for example, 25915 + ... + 26776.

It is an arithmetic number, because the mean of its divisors is an integer number (5690736).

Almost surely, 2^22709821 is an apocalyptic number.

It is an amenable number.

22709821 is a deficient number, since it is larger than the sum of its proper divisors (53123).

22709821 is an equidigital number, since it uses as much as digits as its factorization.

22709821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53122.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 22709821 is about 4765.4822421241. The cubic root of 22709821 is about 283.1856465230.

The spelling of 22709821 in words is "twenty-two million, seven hundred nine thousand, eight hundred twenty-one".