21161761823 has 16 divisors (see below), whose sum is σ = 23396014080. Its totient is φ = 19038577536.

The previous prime is 21161761813. The next prime is 21161761847. The reversal of 21161761823 is 32816716112.

It is a cyclic number.

It is not a de Polignac number, because 21161761823 - 2¹⁴ = 21161745439 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 (21161761813) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 611498 + ... + 645176.

It is an arithmetic number, because the mean of its divisors is an integer number (1462250880).

Almost surely, 2^21161761823 is an apocalyptic number.

21161761823 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

21161761823 is a deficient number, since it is larger than the sum of its proper divisors (2234252257).

21161761823 is a wasteful number, since it uses less digits than its factorization.

21161761823 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35326.

The product of its digits is 24192, while the sum is 38.

The spelling of 21161761823 in words is "twenty-one billion, one hundred sixty-one million, seven hundred sixty-one thousand, eight hundred twenty-three".