21724111523 has 2 divisors, whose sum is σ = 21724111524. Its totient is φ = 21724111522.

The previous prime is 21724111463. The next prime is 21724111559. The reversal of 21724111523 is 32511142712.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21724111523 - 2⁸ = 21724111267 is a prime.

It is not a weakly prime, because it can be changed into another prime (21724111573) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10862055761 + 10862055762.

It is an arithmetic number, because the mean of its divisors is an integer number (10862055762).

Almost surely, 2^21724111523 is an apocalyptic number.

21724111523 is a deficient number, since it is larger than the sum of its proper divisors (1).

21724111523 is an equidigital number, since it uses as much as digits as its factorization.

21724111523 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3360, while the sum is 29.

The spelling of 21724111523 in words is "twenty-one billion, seven hundred twenty-four million, one hundred eleven thousand, five hundred twenty-three".