21011110155 has 32 divisors (see below), whose sum is σ = 42689241600. Its totient is φ = 9605078496.

The previous prime is 21011110111. The next prime is 21011110181. The reversal of 21011110155 is 55101111012.

It is not a de Polignac number, because 21011110155 - 2¹² = 21011106059 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11116045 + ... + 11117934.

It is an arithmetic number, because the mean of its divisors is an integer number (1334038800).

Almost surely, 2^21011110155 is an apocalyptic number.

21011110155 is an abundant number, since it is smaller than the sum of its proper divisors (21678131445).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21011110155 is a wasteful number, since it uses less digits than its factorization.

21011110155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22234000 (or 22233994 counting only the distinct ones).

The product of its (nonzero) digits is 50, while the sum is 18.

Adding to 21011110155 its reverse (55101111012), we get a palindrome (76112221167).

The spelling of 21011110155 in words is "twenty-one billion, eleven million, one hundred ten thousand, one hundred fifty-five".