21142420423 has 4 divisors (see below), whose sum is σ = 21142780848. Its totient is φ = 21142060000.

The previous prime is 21142420421. The next prime is 21142420441. The reversal of 21142420423 is 32402424112.

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 21142420423 - 2¹ = 21142420421 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 (21142420421) 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, 69586 + ... + 217087.

It is an arithmetic number, because the mean of its divisors is an integer number (5285695212).

Almost surely, 2^21142420423 is an apocalyptic number.

21142420423 is a deficient number, since it is larger than the sum of its proper divisors (360425).

21142420423 is an equidigital number, since it uses as much as digits as its factorization.

21142420423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360424.

The product of its (nonzero) digits is 3072, while the sum is 25.

Adding to 21142420423 its reverse (32402424112), we get a palindrome (53544844535).

The spelling of 21142420423 in words is "twenty-one billion, one hundred forty-two million, four hundred twenty thousand, four hundred twenty-three".