21433638 has 32 divisors (see below), whose sum is σ = 43960320. Its totient is φ = 6964640.

The previous prime is 21433613. The next prime is 21433649. The reversal of 21433638 is 83633412.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67456 + ... + 67772.

It is an arithmetic number, because the mean of its divisors is an integer number (1373760).

Almost surely, 2^21433638 is an apocalyptic number.

21433638 is an abundant number, since it is smaller than the sum of its proper divisors (22526682).

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

21433638 is a wasteful number, since it uses less digits than its factorization.

21433638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 572.

The product of its digits is 10368, while the sum is 30.

The square root of 21433638 is about 4629.6477187795. The cubic root of 21433638 is about 277.7785013433.

The spelling of 21433638 in words is "twenty-one million, four hundred thirty-three thousand, six hundred thirty-eight".