21521124523 has 2 divisors, whose sum is σ = 21521124524. Its totient is φ = 21521124522.

The previous prime is 21521124491. The next prime is 21521124529. The reversal of 21521124523 is 32542112512.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21521124523 - 2⁵ = 21521124491 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21521124491 and 21521124500.

It is not a weakly prime, because it can be changed into another prime (21521124529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10760562261 + 10760562262.

It is an arithmetic number, because the mean of its divisors is an integer number (10760562262).

Almost surely, 2^21521124523 is an apocalyptic number.

21521124523 is a deficient number, since it is larger than the sum of its proper divisors (1).

21521124523 is an equidigital number, since it uses as much as digits as its factorization.

21521124523 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4800, while the sum is 28.

The spelling of 21521124523 in words is "twenty-one billion, five hundred twenty-one million, one hundred twenty-four thousand, five hundred twenty-three".