21009182 has 4 divisors (see below), whose sum is σ = 31513776. Its totient is φ = 10504590.

The previous prime is 21009173. The next prime is 21009199. The reversal of 21009182 is 28190012.

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

It is a plaindrome in base 13.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5252294 + ... + 5252297.

It is an arithmetic number, because the mean of its divisors is an integer number (7878444).

Almost surely, 2^21009182 is an apocalyptic number.

21009182 is a deficient number, since it is larger than the sum of its proper divisors (10504594).

21009182 is a wasteful number, since it uses less digits than its factorization.

21009182 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10504593.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 21009182 is about 4583.5774238034. The cubic root of 21009182 is about 275.9326220041.

Adding to 21009182 its reverse (28190012), we get a palindrome (49199194).

The spelling of 21009182 in words is "twenty-one million, nine thousand, one hundred eighty-two".