21520523212423 has 2 divisors, whose sum is σ = 21520523212424. Its totient is φ = 21520523212422.

The previous prime is 21520523212373. The next prime is 21520523212543. The reversal of 21520523212423 is 32421232502512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21520523212423 - 2³⁷ = 21383084258951 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21520529212423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10760261606211 + 10760261606212.

It is an arithmetic number, because the mean of its divisors is an integer number (10760261606212).

Almost surely, 2^{21520523212423} is an apocalyptic number.

21520523212423 is a deficient number, since it is larger than the sum of its proper divisors (1).

21520523212423 is an equidigital number, since it uses as much as digits as its factorization.

21520523212423 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 57600, while the sum is 34.

Adding to 21520523212423 its reverse (32421232502512), we get a palindrome (53941755714935).

The spelling of 21520523212423 in words is "twenty-one trillion, five hundred twenty billion, five hundred twenty-three million, two hundred twelve thousand, four hundred twenty-three".