21923289 has 6 divisors (see below), whose sum is σ = 31666986. Its totient is φ = 14615520.

The previous prime is 21923273. The next prime is 21923299. The reversal of 21923289 is 98232912.

It can be written as a sum of positive squares in only one way, i.e., 14953689 + 6969600 = 3867^2 + 2640^2 .

It is not a de Polignac number, because 21923289 - 2⁴ = 21923273 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21923269) 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 5 ways as a sum of consecutive naturals, for example, 1217952 + ... + 1217969.

It is an arithmetic number, because the mean of its divisors is an integer number (5277831).

Almost surely, 2^21923289 is an apocalyptic number.

It is an amenable number.

21923289 is a deficient number, since it is larger than the sum of its proper divisors (9743697).

21923289 is a wasteful number, since it uses less digits than its factorization.

21923289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2435927 (or 2435924 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 21923289 is about 4682.2311989051. The cubic root of 21923289 is about 279.8778761644.

It can be divided in two parts, 2 and 1923289, that added together give a palindrome (1923291).

The spelling of 21923289 in words is "twenty-one million, nine hundred twenty-three thousand, two hundred eighty-nine".