21663256143 has 8 divisors (see below), whose sum is σ = 28885134256. Its totient is φ = 14441774400.

The previous prime is 21663256129. The next prime is 21663256171. The reversal of 21663256143 is 34165236612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21663256143 - 2¹² = 21663252047 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 (21663256183) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69333 + ... + 219393.

It is an arithmetic number, because the mean of its divisors is an integer number (3610641782).

Almost surely, 2^21663256143 is an apocalyptic number.

21663256143 is a deficient number, since it is larger than the sum of its proper divisors (7221878113).

21663256143 is a wasteful number, since it uses less digits than its factorization.

21663256143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 198185.

The product of its digits is 155520, while the sum is 39.

The spelling of 21663256143 in words is "twenty-one billion, six hundred sixty-three million, two hundred fifty-six thousand, one hundred forty-three".