21361536 has 128 divisors (see below), whose sum is σ = 72134400. Its totient is φ = 6096384.

The previous prime is 21361519. The next prime is 21361579. The reversal of 21361536 is 63516312.

21361536 is a `hidden beast` number, since 2 + 13 + 615 + 36 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 23751 + ... + 24633.

It is an arithmetic number, because the mean of its divisors is an integer number (563550).

Almost surely, 2^21361536 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 21361536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36067200).

21361536 is an abundant number, since it is smaller than the sum of its proper divisors (50772864).

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

21361536 is an equidigital number, since it uses as much as digits as its factorization.

21361536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 913 (or 895 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 21361536 is about 4621.8541733811. The cubic root of 21361536 is about 277.4666724037.

Adding to 21361536 its reverse (63516312), we get a palindrome (84877848).

The spelling of 21361536 in words is "twenty-one million, three hundred sixty-one thousand, five hundred thirty-six".