21121031110123 has 12 divisors (see below), whose sum is σ = 24569559886872. Its totient is φ = 18103595670720.

The previous prime is 21121031110093. The next prime is 21121031110159. The reversal of 21121031110123 is 32101113012112.

It is not a de Polignac number, because 21121031110123 - 2¹³ = 21121031101931 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21121031110123.

It is not an unprimeable number, because it can be changed into a prime (21121031110523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4678588 + ... + 8008198.

It is an arithmetic number, because the mean of its divisors is an integer number (2047463323906).

Almost surely, 2^{21121031110123} is an apocalyptic number.

21121031110123 is a deficient number, since it is larger than the sum of its proper divisors (3448528776749).

21121031110123 is a wasteful number, since it uses less digits than its factorization.

21121031110123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3459082 (or 3459075 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 19.

Adding to 21121031110123 its reverse (32101113012112), we get a palindrome (53222144122235).

The spelling of 21121031110123 in words is "twenty-one trillion, one hundred twenty-one billion, thirty-one million, one hundred ten thousand, one hundred twenty-three".