21020312213123 has 4 divisors (see below), whose sum is σ = 21020321395320. Its totient is φ = 21020303030928.

The previous prime is 21020312213071. The next prime is 21020312213129. The reversal of 21020312213123 is 32131221302012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21020312213123 - 2¹⁰ = 21020312212099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21020312213129) 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, 1934711 + ... + 6766367.

It is an arithmetic number, because the mean of its divisors is an integer number (5255080348830).

Almost surely, 2^{21020312213123} is an apocalyptic number.

21020312213123 is a deficient number, since it is larger than the sum of its proper divisors (9182197).

21020312213123 is an equidigital number, since it uses as much as digits as its factorization.

21020312213123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9182196.

The product of its (nonzero) digits is 864, while the sum is 23.

Adding to 21020312213123 its reverse (32131221302012), we get a palindrome (53151533515135).

The spelling of 21020312213123 in words is "twenty-one trillion, twenty billion, three hundred twelve million, two hundred thirteen thousand, one hundred twenty-three".