21585738 has 16 divisors (see below), whose sum is σ = 43234560. Its totient is φ = 7184736.

The previous prime is 21585719. The next prime is 21585743. The reversal of 21585738 is 83758512.

It is a junction number, because it is equal to n+sod(n) for n = 21585696 and 21585705.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2631 + ... + 7077.

It is an arithmetic number, because the mean of its divisors is an integer number (2702160).

Almost surely, 2^21585738 is an apocalyptic number.

21585738 is an abundant number, since it is smaller than the sum of its proper divisors (21648822).

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

21585738 is a wasteful number, since it uses less digits than its factorization.

21585738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5261.

The product of its digits is 67200, while the sum is 39.

The square root of 21585738 is about 4646.0454151891. The cubic root of 21585738 is about 278.4340217621.

The spelling of 21585738 in words is "twenty-one million, five hundred eighty-five thousand, seven hundred thirty-eight".