21643502850 has 36 divisors (see below), whose sum is σ = 58148878866. Its totient is φ = 5771600640.

The previous prime is 21643502827. The next prime is 21643502861. The reversal of 21643502850 is 5820534612.

21643502850 is a `hidden beast` number, since 2 + 1 + 643 + 5 + 0 + 2 + 8 + 5 + 0 = 666.

21643502850 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 12090981681 + 9552521169 = 109959^2 + 97737^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 24047887 + ... + 24048786.

Almost surely, 2^21643502850 is an apocalyptic number.

21643502850 is an abundant number, since it is smaller than the sum of its proper divisors (36505376016).

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

21643502850 is a wasteful number, since it uses less digits than its factorization.

21643502850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48096691 (or 48096683 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The spelling of 21643502850 in words is "twenty-one billion, six hundred forty-three million, five hundred two thousand, eight hundred fifty".