21421186 has 16 divisors (see below), whose sum is σ = 33488640. Its totient is φ = 10265040.

The previous prime is 21421177. The next prime is 21421201. The reversal of 21421186 is 68112412.

It is a self number, because there is not a number n which added to its sum of digits gives 21421186.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 5020 + ... + 8248.

It is an arithmetic number, because the mean of its divisors is an integer number (2093040).

Almost surely, 2^21421186 is an apocalyptic number.

21421186 is a deficient number, since it is larger than the sum of its proper divisors (12067454).

21421186 is a wasteful number, since it uses less digits than its factorization.

21421186 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3369.

The product of its digits is 768, while the sum is 25.

The square root of 21421186 is about 4628.3027126583. The cubic root of 21421186 is about 277.7246985632.

Adding to 21421186 its reverse (68112412), we get a palindrome (89533598).

The spelling of 21421186 in words is "twenty-one million, four hundred twenty-one thousand, one hundred eighty-six".