21595500243 has 24 divisors (see below), whose sum is σ = 31542038528. Its totient is φ = 14236880112.

The previous prime is 21595500181. The next prime is 21595500307. The reversal of 21595500243 is 34200559512.

It is a happy number.

21595500243 is a `hidden beast` number, since 21 + 5 + 95 + 500 + 2 + 43 = 666.

It is not a de Polignac number, because 21595500243 - 2¹⁷ = 21595369171 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21595500198 and 21595500207.

It is not an unprimeable number, because it can be changed into a prime (21595500343) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 320130 + ... + 381672.

Almost surely, 2^21595500243 is an apocalyptic number.

21595500243 is a deficient number, since it is larger than the sum of its proper divisors (9946538285).

21595500243 is a wasteful number, since it uses less digits than its factorization.

21595500243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61983 (or 61980 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 36.

The spelling of 21595500243 in words is "twenty-one billion, five hundred ninety-five million, five hundred thousand, two hundred forty-three".