21042013202123 has 4 divisors (see below), whose sum is σ = 21042175639128. Its totient is φ = 21041850765120.

The previous prime is 21042013202117. The next prime is 21042013202207. The reversal of 21042013202123 is 32120231024012.

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 21042013202123 - 2²⁴ = 21041996424907 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21042013202723) 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, 81024038 + ... + 81283323.

It is an arithmetic number, because the mean of its divisors is an integer number (5260543909782).

Almost surely, 2^{21042013202123} is an apocalyptic number.

21042013202123 is a deficient number, since it is larger than the sum of its proper divisors (162437005).

21042013202123 is a wasteful number, since it uses less digits than its factorization.

21042013202123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162437004.

The product of its (nonzero) digits is 1152, while the sum is 23.

Adding to 21042013202123 its reverse (32120231024012), we get a palindrome (53162244226135).

The spelling of 21042013202123 in words is "twenty-one trillion, forty-two billion, thirteen million, two hundred two thousand, one hundred twenty-three".