21381936 has 40 divisors (see below), whose sum is σ = 55454784. Its totient is φ = 7099200.

The previous prime is 21381931. The next prime is 21381977. The reversal of 21381936 is 63918312.

It is a junction number, because it is equal to n+sod(n) for n = 21381897 and 21381906.

It is not an unprimeable number, because it can be changed into a prime (21381931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14011 + ... + 15461.

Almost surely, 2^21381936 is an apocalyptic number.

It is an amenable number.

21381936 is an abundant number, since it is smaller than the sum of its proper divisors (34072848).

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

21381936 is a wasteful number, since it uses less digits than its factorization.

21381936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1769 (or 1763 counting only the distinct ones).

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

The square root of 21381936 is about 4624.0605532367. The cubic root of 21381936 is about 277.5549700371.

The spelling of 21381936 in words is "twenty-one million, three hundred eighty-one thousand, nine hundred thirty-six".