21636546871 has 2 divisors, whose sum is σ = 21636546872. Its totient is φ = 21636546870.

The previous prime is 21636546859. The next prime is 21636546889. The reversal of 21636546871 is 17864563612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21636546871 - 2¹⁵ = 21636514103 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21636546271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10818273435 + 10818273436.

It is an arithmetic number, because the mean of its divisors is an integer number (10818273436).

Almost surely, 2^21636546871 is an apocalyptic number.

21636546871 is a deficient number, since it is larger than the sum of its proper divisors (1).

21636546871 is an equidigital number, since it uses as much as digits as its factorization.

21636546871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1451520, while the sum is 49.

The spelling of 21636546871 in words is "twenty-one billion, six hundred thirty-six million, five hundred forty-six thousand, eight hundred seventy-one".