21211386 has 16 divisors (see below), whose sum is σ = 48483264. Its totient is φ = 6060384.

The previous prime is 21211381. The next prime is 21211387. The reversal of 21211386 is 68311212.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21211381) 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 7 ways as a sum of consecutive naturals, for example, 252475 + ... + 252558.

It is an arithmetic number, because the mean of its divisors is an integer number (3030204).

Almost surely, 2^21211386 is an apocalyptic number.

21211386 is an abundant number, since it is smaller than the sum of its proper divisors (27271878).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21211386 is a wasteful number, since it uses less digits than its factorization.

21211386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 505045.

The product of its digits is 576, while the sum is 24.

The square root of 21211386 is about 4605.5820479066. The cubic root of 21211386 is about 276.8150398485.

Adding to 21211386 its reverse (68311212), we get a palindrome (89522598).

The spelling of 21211386 in words is "twenty-one million, two hundred eleven thousand, three hundred eighty-six".