21895447663 has 4 divisors (see below), whose sum is σ = 21895752928. Its totient is φ = 21895142400.

The previous prime is 21895447649. The next prime is 21895447667. The reversal of 21895447663 is 36674459812.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21895447663 - 2⁵ = 21895447631 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21895447667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20170 + ... + 210232.

It is an arithmetic number, because the mean of its divisors is an integer number (5473938232).

Almost surely, 2^21895447663 is an apocalyptic number.

21895447663 is a deficient number, since it is larger than the sum of its proper divisors (305265).

21895447663 is a wasteful number, since it uses less digits than its factorization.

21895447663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305264.

The product of its digits is 8709120, while the sum is 55.

The spelling of 21895447663 in words is "twenty-one billion, eight hundred ninety-five million, four hundred forty-seven thousand, six hundred sixty-three".