21738535 has 16 divisors (see below), whose sum is σ = 32106816. Its totient is φ = 13759488.

The previous prime is 21738503. The next prime is 21738539. The reversal of 21738535 is 53583712.

It is a cyclic number.

It is not a de Polignac number, because 21738535 - 2⁵ = 21738503 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21738535.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21738539) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 23434 + ... + 24343.

It is an arithmetic number, because the mean of its divisors is an integer number (2006676).

Almost surely, 2^21738535 is an apocalyptic number.

21738535 is a deficient number, since it is larger than the sum of its proper divisors (10368281).

21738535 is a wasteful number, since it uses less digits than its factorization.

21738535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47802.

The product of its digits is 25200, while the sum is 34.

The square root of 21738535 is about 4662.4601874976. The cubic root of 21738535 is about 279.0894528666.

The spelling of 21738535 in words is "twenty-one million, seven hundred thirty-eight thousand, five hundred thirty-five".