21242936 has 64 divisors (see below), whose sum is σ = 48384000. Its totient is φ = 8611200.

The previous prime is 21242917. The next prime is 21242939. The reversal of 21242936 is 63924212.

It is a junction number, because it is equal to n+sod(n) for n = 21242899 and 21242908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242939) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35165 + ... + 35763.

It is an arithmetic number, because the mean of its divisors is an integer number (756000).

Almost surely, 2^21242936 is an apocalyptic number.

21242936 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21242936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24192000).

21242936 is an abundant number, since it is smaller than the sum of its proper divisors (27141064).

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

21242936 is a wasteful number, since it uses less digits than its factorization.

21242936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 660 (or 656 counting only the distinct ones).

The product of its digits is 5184, while the sum is 29.

The square root of 21242936 is about 4609.0059665833. The cubic root of 21242936 is about 276.9522175570.

The spelling of 21242936 in words is "twenty-one million, two hundred forty-two thousand, nine hundred thirty-six".