21616202155 has 4 divisors (see below), whose sum is σ = 25939442592. Its totient is φ = 17292961720.

The previous prime is 21616202119. The next prime is 21616202159. The reversal of 21616202155 is 55120261612.

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

It is not a de Polignac number, because 21616202155 - 2⁹ = 21616201643 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21616202159) 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, 2161620211 + ... + 2161620220.

It is an arithmetic number, because the mean of its divisors is an integer number (6484860648).

Almost surely, 2^21616202155 is an apocalyptic number.

21616202155 is a deficient number, since it is larger than the sum of its proper divisors (4323240437).

21616202155 is an equidigital number, since it uses as much as digits as its factorization.

21616202155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4323240436.

The product of its (nonzero) digits is 7200, while the sum is 31.

Adding to 21616202155 its reverse (55120261612), we get a palindrome (76736463767).

The spelling of 21616202155 in words is "twenty-one billion, six hundred sixteen million, two hundred two thousand, one hundred fifty-five".