21821428523 has 2 divisors, whose sum is σ = 21821428524. Its totient is φ = 21821428522.

The previous prime is 21821428481. The next prime is 21821428553. The reversal of 21821428523 is 32582412812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21821428523 - 2⁶ = 21821428459 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21821428553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10910714261 + 10910714262.

It is an arithmetic number, because the mean of its divisors is an integer number (10910714262).

Almost surely, 2^21821428523 is an apocalyptic number.

21821428523 is a deficient number, since it is larger than the sum of its proper divisors (1).

21821428523 is an equidigital number, since it uses as much as digits as its factorization.

21821428523 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61440, while the sum is 38.

The spelling of 21821428523 in words is "twenty-one billion, eight hundred twenty-one million, four hundred twenty-eight thousand, five hundred twenty-three".