21536738 has 8 divisors (see below), whose sum is σ = 33178332. Its totient is φ = 10477296.

The previous prime is 21536737. The next prime is 21536741. The reversal of 21536738 is 83763512.

It can be written as a sum of positive squares in 2 ways, for example, as 21501769 + 34969 = 4637^2 + 187^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21536698 and 21536707.

It is not an unprimeable number, because it can be changed into a prime (21536737) 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 3 ways as a sum of consecutive naturals, for example, 145445 + ... + 145592.

Almost surely, 2^21536738 is an apocalyptic number.

21536738 is a deficient number, since it is larger than the sum of its proper divisors (11641594).

21536738 is a wasteful number, since it uses less digits than its factorization.

21536738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291076.

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

The square root of 21536738 is about 4640.7691172908. The cubic root of 21536738 is about 278.2231787881.

The spelling of 21536738 in words is "twenty-one million, five hundred thirty-six thousand, seven hundred thirty-eight".