21813814 has 16 divisors (see below), whose sum is σ = 36527040. Its totient is φ = 9684360.

The previous prime is 21813809. The next prime is 21813817. The reversal of 21813814 is 41831812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21813817) 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, 10584 + ... + 12475.

It is an arithmetic number, because the mean of its divisors is an integer number (2282940).

Almost surely, 2^21813814 is an apocalyptic number.

21813814 is a deficient number, since it is larger than the sum of its proper divisors (14713226).

21813814 is a wasteful number, since it uses less digits than its factorization.

21813814 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23115.

The product of its digits is 1536, while the sum is 28.

The square root of 21813814 is about 4670.5260945637. The cubic root of 21813814 is about 279.4112373523.

It can be divided in two parts, 2181 and 3814, that added together give a palindrome (5995).

The spelling of 21813814 in words is "twenty-one million, eight hundred thirteen thousand, eight hundred fourteen".