21256476823 has 2 divisors, whose sum is σ = 21256476824. Its totient is φ = 21256476822.

The previous prime is 21256476701. The next prime is 21256476859. The reversal of 21256476823 is 32867465212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21256476823 - 2¹⁷ = 21256345751 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21256476023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10628238411 + 10628238412.

It is an arithmetic number, because the mean of its divisors is an integer number (10628238412).

Almost surely, 2^21256476823 is an apocalyptic number.

21256476823 is a deficient number, since it is larger than the sum of its proper divisors (1).

21256476823 is an equidigital number, since it uses as much as digits as its factorization.

21256476823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 967680, while the sum is 46.

The spelling of 21256476823 in words is "twenty-one billion, two hundred fifty-six million, four hundred seventy-six thousand, eight hundred twenty-three".