20408636583991 has 2 divisors, whose sum is σ = 20408636583992. Its totient is φ = 20408636583990.

The previous prime is 20408636583961. The next prime is 20408636584009. The reversal of 20408636583991 is 19938563680402.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20408636583991 - 2¹¹ = 20408636581943 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20408636583961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10204318291995 + 10204318291996.

It is an arithmetic number, because the mean of its divisors is an integer number (10204318291996).

Almost surely, 2^{20408636583991} is an apocalyptic number.

20408636583991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20408636583991 is an equidigital number, since it uses as much as digits as its factorization.

20408636583991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 67184640, while the sum is 64.

The spelling of 20408636583991 in words is "twenty trillion, four hundred eight billion, six hundred thirty-six million, five hundred eighty-three thousand, nine hundred ninety-one".