21523646239 has 16 divisors (see below), whose sum is σ = 22342942720. Its totient is φ = 20712386880.

The previous prime is 21523646197. The next prime is 21523646257. The reversal of 21523646239 is 93264632512.

It is a cyclic number.

It is not a de Polignac number, because 21523646239 - 2¹³ = 21523638047 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21523646195 and 21523646204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523646539) 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 15 ways as a sum of consecutive naturals, for example, 11453902 + ... + 11455780.

It is an arithmetic number, because the mean of its divisors is an integer number (1396433920).

Almost surely, 2^21523646239 is an apocalyptic number.

21523646239 is a deficient number, since it is larger than the sum of its proper divisors (819296481).

21523646239 is a wasteful number, since it uses less digits than its factorization.

21523646239 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3790.

The product of its digits is 466560, while the sum is 43.

The spelling of 21523646239 in words is "twenty-one billion, five hundred twenty-three million, six hundred forty-six thousand, two hundred thirty-nine".