21605650236 has 48 divisors (see below), whose sum is σ = 56390628000. Its totient is φ = 7153543296.

The previous prime is 21605650223. The next prime is 21605650271. The reversal of 21605650236 is 63205650612.

It is a happy number.

21605650236 is a `hidden beast` number, since 2 + 1 + 60 + 565 + 0 + 2 + 36 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21605650236.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 655225 + ... + 687408.

It is an arithmetic number, because the mean of its divisors is an integer number (1174804750).

Almost surely, 2^21605650236 is an apocalyptic number.

It is an amenable number.

21605650236 is an abundant number, since it is smaller than the sum of its proper divisors (34784977764).

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

21605650236 is a wasteful number, since it uses less digits than its factorization.

21605650236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1342795 (or 1342787 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The spelling of 21605650236 in words is "twenty-one billion, six hundred five million, six hundred fifty thousand, two hundred thirty-six".