21424236 has 24 divisors (see below), whose sum is σ = 50183280. Its totient is φ = 7113792.

The previous prime is 21424223. The next prime is 21424241. The reversal of 21424236 is 63242412.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91 + ... + 6546.

It is an arithmetic number, because the mean of its divisors is an integer number (2090970).

Almost surely, 2^21424236 is an apocalyptic number.

It is an amenable number.

21424236 is an abundant number, since it is smaller than the sum of its proper divisors (28759044).

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

21424236 is a wasteful number, since it uses less digits than its factorization.

21424236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6913 (or 6911 counting only the distinct ones).

The product of its digits is 2304, while the sum is 24.

The square root of 21424236 is about 4628.6321953683. The cubic root of 21424236 is about 277.7378789746.

Adding to 21424236 its reverse (63242412), we get a palindrome (84666648).

The spelling of 21424236 in words is "twenty-one million, four hundred twenty-four thousand, two hundred thirty-six".