21738536 has 24 divisors (see below), whose sum is σ = 42016410. Its totient is φ = 10536480.

The previous prime is 21738503. The next prime is 21738539. The reversal of 21738536 is 63583712.

It can be written as a sum of positive squares in only one way, i.e., 14394436 + 7344100 = 3794^2 + 2710^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21738496 and 21738505.

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 (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 80081 + ... + 80351.

Almost surely, 2^21738536 is an apocalyptic number.

It is an amenable number.

21738536 is a deficient number, since it is larger than the sum of its proper divisors (20277874).

21738536 is an equidigital number, since it uses as much as digits as its factorization.

21738536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 585 (or 310 counting only the distinct ones).

The product of its digits is 30240, while the sum is 35.

The square root of 21738536 is about 4662.4602947371. The cubic root of 21738536 is about 279.0894571461.

The spelling of 21738536 in words is "twenty-one million, seven hundred thirty-eight thousand, five hundred thirty-six".