21204936 has 64 divisors (see below), whose sum is σ = 59443200. Its totient is φ = 7003584.

The previous prime is 21204917. The next prime is 21204947. The reversal of 21204936 is 63940212.

It is a super-3 number, since 3×21204936³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27046 + ... + 27818.

It is an arithmetic number, because the mean of its divisors is an integer number (928800).

Almost surely, 2^21204936 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21204936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29721600).

21204936 is an abundant number, since it is smaller than the sum of its proper divisors (38238264).

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

21204936 is a wasteful number, since it uses less digits than its factorization.

21204936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 915 (or 905 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 21204936 is about 4604.8817574396. The cubic root of 21204936 is about 276.7869788500.

It can be divided in two parts, 2120 and 4936, that added together give a square (7056 = 84²).

The spelling of 21204936 in words is "twenty-one million, two hundred four thousand, nine hundred thirty-six".