21169536 has 64 divisors (see below), whose sum is σ = 58201200. Its totient is φ = 6809600.

The previous prime is 21169481. The next prime is 21169537. The reversal of 21169536 is 63596112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a junction number, because it is equal to n+sod(n) for n = 21169497 and 21169506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21169537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10186 + ... + 12086.

Almost surely, 2^21169536 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21169536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29100600).

21169536 is an abundant number, since it is smaller than the sum of its proper divisors (37031664).

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

21169536 is a wasteful number, since it uses less digits than its factorization.

21169536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1947 (or 1935 counting only the distinct ones).

The product of its digits is 9720, while the sum is 33.

The square root of 21169536 is about 4601.0364049853. The cubic root of 21169536 is about 276.6328682443.

The spelling of 21169536 in words is "twenty-one million, one hundred sixty-nine thousand, five hundred thirty-six".