21321936 has 60 divisors (see below), whose sum is σ = 60005088. Its totient is φ = 7067712.

The previous prime is 21321929. The next prime is 21321941. The reversal of 21321936 is 63912312.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37591 + ... + 38153.

Almost surely, 2^21321936 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 21321936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30002544).

21321936 is an abundant number, since it is smaller than the sum of its proper divisors (38683152).

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

21321936 is a wasteful number, since it uses less digits than its factorization.

21321936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840 (or 831 counting only the distinct ones).

The product of its digits is 1944, while the sum is 27.

The square root of 21321936 is about 4617.5681911586. The cubic root of 21321936 is about 277.2951105073.

The spelling of 21321936 in words is "twenty-one million, three hundred twenty-one thousand, nine hundred thirty-six".