21115213055 has 32 divisors (see below), whose sum is σ = 27086400000. Its totient is φ = 15766732800.

The previous prime is 21115213051. The next prime is 21115213061. The reversal of 21115213055 is 55031251112.

It is not a de Polignac number, because 21115213055 - 2² = 21115213051 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115213051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5612375 + ... + 5616135.

It is an arithmetic number, because the mean of its divisors is an integer number (846450000).

Almost surely, 2^21115213055 is an apocalyptic number.

21115213055 is a deficient number, since it is larger than the sum of its proper divisors (5971186945).

21115213055 is a wasteful number, since it uses less digits than its factorization.

21115213055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5075.

The product of its (nonzero) digits is 1500, while the sum is 26.

Adding to 21115213055 its reverse (55031251112), we get a palindrome (76146464167).

The spelling of 21115213055 in words is "twenty-one billion, one hundred fifteen million, two hundred thirteen thousand, fifty-five".