21606500139 has 16 divisors (see below), whose sum is σ = 32936713728. Its totient is φ = 12341875392.

The previous prime is 21606500119. The next prime is 21606500177. The reversal of 21606500139 is 93100560612.

It is a happy number.

It is not a de Polignac number, because 21606500139 - 2⁵ = 21606500107 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21606500119) 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, 138762 + ... + 249935.

It is an arithmetic number, because the mean of its divisors is an integer number (2058544608).

Almost surely, 2^21606500139 is an apocalyptic number.

21606500139 is a deficient number, since it is larger than the sum of its proper divisors (11330213589).

21606500139 is a wasteful number, since it uses less digits than its factorization.

21606500139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 391354.

The product of its (nonzero) digits is 9720, while the sum is 33.

The spelling of 21606500139 in words is "twenty-one billion, six hundred six million, five hundred thousand, one hundred thirty-nine".