21636541871 has 12 divisors (see below), whose sum is σ = 25242437232. Its totient is φ = 18545592912.

The previous prime is 21636541847. The next prime is 21636541919. The reversal of 21636541871 is 17814563612.

It is not a de Polignac number, because 21636541871 - 2¹⁴ = 21636525487 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 (21636546871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 626870 + ... + 660483.

It is an arithmetic number, because the mean of its divisors is an integer number (2103536436).

Almost surely, 2^21636541871 is an apocalyptic number.

21636541871 is a deficient number, since it is larger than the sum of its proper divisors (3605895361).

21636541871 is an frugal number, since it uses more digits than its factorization.

21636541871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1287388 (or 1287360 counting only the distinct ones).

The product of its digits is 241920, while the sum is 44.

The spelling of 21636541871 in words is "twenty-one billion, six hundred thirty-six million, five hundred forty-one thousand, eight hundred seventy-one".