21618036536111 has 4 divisors (see below), whose sum is σ = 21940693797912. Its totient is φ = 21295379274312.

The previous prime is 21618036536039. The next prime is 21618036536149. The reversal of 21618036536111 is 11163563081612.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21618036536111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21618036536191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 161328630800 + ... + 161328630933.

It is an arithmetic number, because the mean of its divisors is an integer number (5485173449478).

Almost surely, 2^{21618036536111} is an apocalyptic number.

21618036536111 is a deficient number, since it is larger than the sum of its proper divisors (322657261801).

21618036536111 is an equidigital number, since it uses as much as digits as its factorization.

21618036536111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322657261800.

The product of its (nonzero) digits is 155520, while the sum is 44.

The spelling of 21618036536111 in words is "twenty-one trillion, six hundred eighteen billion, thirty-six million, five hundred thirty-six thousand, one hundred eleven".