21000123020311 has 4 divisors (see below), whose sum is σ = 21000132987912. Its totient is φ = 21000113052712.

The previous prime is 21000123020299. The next prime is 21000123020353. The reversal of 21000123020311 is 11302032100012.

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 21000123020311 - 2²³ = 21000114631703 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000123023311) 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, 446776 + ... + 6496141.

It is an arithmetic number, because the mean of its divisors is an integer number (5250033246978).

Almost surely, 2^{21000123020311} is an apocalyptic number.

21000123020311 is a deficient number, since it is larger than the sum of its proper divisors (9967601).

21000123020311 is an equidigital number, since it uses as much as digits as its factorization.

21000123020311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9967600.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21000123020311 its reverse (11302032100012), we get a palindrome (32302155120323).

The spelling of 21000123020311 in words is "twenty-one trillion, one hundred twenty-three million, twenty thousand, three hundred eleven".