21842492 has 24 divisors (see below), whose sum is σ = 43784160. Its totient is φ = 9339840.

The previous prime is 21842477. The next prime is 21842497. The reversal of 21842492 is 29424812.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21842497) 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, 22742 + ... + 23682.

It is an arithmetic number, because the mean of its divisors is an integer number (1824340).

Almost surely, 2^21842492 is an apocalyptic number.

It is an amenable number.

21842492 is an abundant number, since it is smaller than the sum of its proper divisors (21941668).

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

21842492 is a wasteful number, since it uses less digits than its factorization.

21842492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1781 (or 1779 counting only the distinct ones).

The product of its digits is 9216, while the sum is 32.

The square root of 21842492 is about 4673.5951900009. The cubic root of 21842492 is about 279.5336283986.

The spelling of 21842492 in words is "twenty-one million, eight hundred forty-two thousand, four hundred ninety-two".