21621212334163 has 8 divisors (see below), whose sum is σ = 24296746971168. Its totient is φ = 19090301191104.

The previous prime is 21621212334109. The next prime is 21621212334187. The reversal of 21621212334163 is 36143321212612.

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

It is a de Polignac number, because none of the positive numbers 2^k-21621212334163 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21621212334103) 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, 36155873170 + ... + 36155873767.

It is an arithmetic number, because the mean of its divisors is an integer number (3037093371396).

Almost surely, 2^{21621212334163} is an apocalyptic number.

21621212334163 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21621212334163 is a deficient number, since it is larger than the sum of its proper divisors (2675534637005).

21621212334163 is a wasteful number, since it uses less digits than its factorization.

21621212334163 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72311746973.

The product of its digits is 62208, while the sum is 37.

Adding to 21621212334163 its reverse (36143321212612), we get a palindrome (57764533546775).

The spelling of 21621212334163 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred twelve million, three hundred thirty-four thousand, one hundred sixty-three".