21831936 has 144 divisors (see below), whose sum is σ = 69070848. Its totient is φ = 5990400.

The previous prime is 21831913. The next prime is 21831941. The reversal of 21831936 is 63913812.

It is a junction number, because it is equal to n+sod(n) for n = 21831897 and 21831906.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 166591 + ... + 166721.

Almost surely, 2^21831936 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 21831936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34535424).

21831936 is an abundant number, since it is smaller than the sum of its proper divisors (47238912).

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

21831936 is a wasteful number, since it uses less digits than its factorization.

21831936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188 (or 174 counting only the distinct ones).

The product of its digits is 7776, while the sum is 33.

The square root of 21831936 is about 4672.4657302114. The cubic root of 21831936 is about 279.4885903072.

The spelling of 21831936 in words is "twenty-one million, eight hundred thirty-one thousand, nine hundred thirty-six".