21945814 has 16 divisors (see below), whose sum is σ = 35994816. Its totient is φ = 9952200.

The previous prime is 21945811. The next prime is 21945821. The reversal of 21945814 is 41854912.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21945814.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21945811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11689 + ... + 13435.

It is an arithmetic number, because the mean of its divisors is an integer number (2249676).

Almost surely, 2^21945814 is an apocalyptic number.

21945814 is a deficient number, since it is larger than the sum of its proper divisors (14049002).

21945814 is a wasteful number, since it uses less digits than its factorization.

21945814 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2331.

The product of its digits is 11520, while the sum is 34.

The square root of 21945814 is about 4684.6359517043. The cubic root of 21945814 is about 279.9736965087.

It can be divided in two parts, 2194 and 5814, that added together give a palindrome (8008).

The spelling of 21945814 in words is "twenty-one million, nine hundred forty-five thousand, eight hundred fourteen".