21536744 has 8 divisors (see below), whose sum is σ = 40381410. Its totient is φ = 10768368.

The previous prime is 21536741. The next prime is 21536759. The reversal of 21536744 is 44763512.

It can be written as a sum of positive squares in only one way, i.e., 19096900 + 2439844 = 4370^2 + 1562^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 21536744.

It is not an unprimeable number, because it can be changed into a prime (21536741) 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 as a sum of consecutive naturals, namely, 1346039 + ... + 1346054.

Almost surely, 2^21536744 is an apocalyptic number.

It is an amenable number.

21536744 is a deficient number, since it is larger than the sum of its proper divisors (18844666).

21536744 is a wasteful number, since it uses less digits than its factorization.

21536744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2692099 (or 2692095 counting only the distinct ones).

The product of its digits is 20160, while the sum is 32.

The square root of 21536744 is about 4640.7697637353. The cubic root of 21536744 is about 278.2232046251.

The spelling of 21536744 in words is "twenty-one million, five hundred thirty-six thousand, seven hundred forty-four".