21132155155 has 4 divisors (see below), whose sum is σ = 25358586192. Its totient is φ = 16905724120.

The previous prime is 21132155111. The next prime is 21132155189. The reversal of 21132155155 is 55155123112.

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

It is not a de Polignac number, because 21132155155 - 2⁹ = 21132154643 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 an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2113215511 + ... + 2113215520.

It is an arithmetic number, because the mean of its divisors is an integer number (6339646548).

Almost surely, 2^21132155155 is an apocalyptic number.

21132155155 is a deficient number, since it is larger than the sum of its proper divisors (4226431037).

21132155155 is an equidigital number, since it uses as much as digits as its factorization.

21132155155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4226431036.

The product of its digits is 7500, while the sum is 31.

Adding to 21132155155 its reverse (55155123112), we get a palindrome (76287278267).

The spelling of 21132155155 in words is "twenty-one billion, one hundred thirty-two million, one hundred fifty-five thousand, one hundred fifty-five".