21182089 has 4 divisors (see below), whose sum is σ = 21420180. Its totient is φ = 20944000.

The previous prime is 21182009. The next prime is 21182107. The reversal of 21182089 is 98028112.

It is a happy number.

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 7617600 + 13564489 = 2760^2 + 3683^2 .

It is a cyclic number.

It is not a de Polignac number, because 21182089 - 2⁷ = 21181961 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 self number, because there is not a number n which added to its sum of digits gives 21182089.

It is not an unprimeable number, because it can be changed into a prime (21182009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 118912 + ... + 119089.

It is an arithmetic number, because the mean of its divisors is an integer number (5355045).

Almost surely, 2^21182089 is an apocalyptic number.

It is an amenable number.

21182089 is a deficient number, since it is larger than the sum of its proper divisors (238091).

21182089 is an equidigital number, since it uses as much as digits as its factorization.

21182089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238090.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 21182089 is about 4602.4003519903. The cubic root of 21182089 is about 276.6875362074.

The spelling of 21182089 in words is "twenty-one million, one hundred eighty-two thousand, eighty-nine".