21121110202123 has 4 divisors (see below), whose sum is σ = 21121171158640. Its totient is φ = 21121049245608.

The previous prime is 21121110202067. The next prime is 21121110202139. The reversal of 21121110202123 is 32120201112112.

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

It is a cyclic number.

It is not a de Polignac number, because 21121110202123 - 2¹⁷ = 21121110071051 is a prime.

It is a super-2 number, since 2×21121110202123² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21121110202123.

It is not an unprimeable number, because it can be changed into a prime (21121110202163) 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, 29955528 + ... + 30652501.

It is an arithmetic number, because the mean of its divisors is an integer number (5280292789660).

Almost surely, 2^{21121110202123} is an apocalyptic number.

21121110202123 is a deficient number, since it is larger than the sum of its proper divisors (60956517).

21121110202123 is an equidigital number, since it uses as much as digits as its factorization.

21121110202123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60956516.

The product of its (nonzero) digits is 96, while the sum is 19.

Adding to 21121110202123 its reverse (32120201112112), we get a palindrome (53241311314235).

The spelling of 21121110202123 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred ten million, two hundred two thousand, one hundred twenty-three".