21585736 has 8 divisors (see below), whose sum is σ = 40473270. Its totient is φ = 10792864.

The previous prime is 21585719. The next prime is 21585743. The reversal of 21585736 is 63758512.

It can be written as a sum of positive squares in only one way, i.e., 20160100 + 1425636 = 4490^2 + 1194^2 .

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

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a pancake number, because a pancake can be divided into 21585736 parts by 6570 straight cuts.

It is a junction number, because it is equal to n+sod(n) for n = 21585695 and 21585704.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1349101 + ... + 1349116.

Almost surely, 2^21585736 is an apocalyptic number.

It is an amenable number.

21585736 is a deficient number, since it is larger than the sum of its proper divisors (18887534).

21585736 is a wasteful number, since it uses less digits than its factorization.

21585736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2698223 (or 2698219 counting only the distinct ones).

The product of its digits is 50400, while the sum is 37.

The square root of 21585736 is about 4646.0451999523. The cubic root of 21585736 is about 278.4340131628.

The spelling of 21585736 in words is "twenty-one million, five hundred eighty-five thousand, seven hundred thirty-six".