21525984643 has 2 divisors, whose sum is σ = 21525984644. Its totient is φ = 21525984642.

The previous prime is 21525984637. The next prime is 21525984673. The reversal of 21525984643 is 34648952512.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21525984643 is a prime.

It is not a weakly prime, because it can be changed into another prime (21525984673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10762992321 + 10762992322.

It is an arithmetic number, because the mean of its divisors is an integer number (10762992322).

Almost surely, 2^21525984643 is an apocalyptic number.

21525984643 is a deficient number, since it is larger than the sum of its proper divisors (1).

21525984643 is an equidigital number, since it uses as much as digits as its factorization.

21525984643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2073600, while the sum is 49.

The spelling of 21525984643 in words is "twenty-one billion, five hundred twenty-five million, nine hundred eighty-four thousand, six hundred forty-three".