21563164366 has 4 divisors (see below), whose sum is σ = 32344746552. Its totient is φ = 10781582182.

The previous prime is 21563164331. The next prime is 21563164367. The reversal of 21563164366 is 66346136512.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21563164367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5390791090 + ... + 5390791093.

It is an arithmetic number, because the mean of its divisors is an integer number (8086186638).

Almost surely, 2^21563164366 is an apocalyptic number.

21563164366 is a deficient number, since it is larger than the sum of its proper divisors (10781582186).

21563164366 is a wasteful number, since it uses less digits than its factorization.

21563164366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10781582185.

The product of its digits is 466560, while the sum is 43.

The spelling of 21563164366 in words is "twenty-one billion, five hundred sixty-three million, one hundred sixty-four thousand, three hundred sixty-six".