21609937356099 has 4 divisors (see below), whose sum is σ = 28813249808136. Its totient is φ = 14406624904064.

The previous prime is 21609937356023. The next prime is 21609937356127. The reversal of 21609937356099 is 99065373990612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21609937356099 - 2¹⁷ = 21609937225027 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21609937356199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3601656226014 + ... + 3601656226019.

It is an arithmetic number, because the mean of its divisors is an integer number (7203312452034).

Almost surely, 2^{21609937356099} is an apocalyptic number.

21609937356099 is a deficient number, since it is larger than the sum of its proper divisors (7203312452037).

21609937356099 is an equidigital number, since it uses as much as digits as its factorization.

21609937356099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7203312452036.

The product of its (nonzero) digits is 148803480, while the sum is 69.

The spelling of 21609937356099 in words is "twenty-one trillion, six hundred nine billion, nine hundred thirty-seven million, three hundred fifty-six thousand, ninety-nine".