21355331423 has 2 divisors, whose sum is σ = 21355331424. Its totient is φ = 21355331422.

The previous prime is 21355331411. The next prime is 21355331441. The reversal of 21355331423 is 32413355312.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21355331423 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21355331423.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21355331453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10677665711 + 10677665712.

It is an arithmetic number, because the mean of its divisors is an integer number (10677665712).

Almost surely, 2^21355331423 is an apocalyptic number.

21355331423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21355331423 is an equidigital number, since it uses as much as digits as its factorization.

21355331423 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32400, while the sum is 32.

Adding to 21355331423 its reverse (32413355312), we get a palindrome (53768686735).

The spelling of 21355331423 in words is "twenty-one billion, three hundred fifty-five million, three hundred thirty-one thousand, four hundred twenty-three".