21245536 has 24 divisors (see below), whose sum is σ = 45045504. Its totient is φ = 9805440.

The previous prime is 21245533. The next prime is 21245557. The reversal of 21245536 is 63554212.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21245531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25120 + ... + 25951.

It is an arithmetic number, because the mean of its divisors is an integer number (1876896).

Almost surely, 2^21245536 is an apocalyptic number.

21245536 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21245536 is an abundant number, since it is smaller than the sum of its proper divisors (23799968).

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

21245536 is a wasteful number, since it uses less digits than its factorization.

21245536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51094 (or 51086 counting only the distinct ones).

The product of its digits is 7200, while the sum is 28.

The square root of 21245536 is about 4609.2880144335. The cubic root of 21245536 is about 276.9635161583.

Adding to 21245536 its reverse (63554212), we get a palindrome (84799748).

The spelling of 21245536 in words is "twenty-one million, two hundred forty-five thousand, five hundred thirty-six".