20001549631993 has 2 divisors, whose sum is σ = 20001549631994. Its totient is φ = 20001549631992.

The previous prime is 20001549631891. The next prime is 20001549632047. The reversal of 20001549631993 is 39913694510002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17633927322729 + 2367622309264 = 4199277^2 + 1538708^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20001549631993 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20001549631993.

It is not a weakly prime, because it can be changed into another prime (20001549631793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10000774815996 + 10000774815997.

It is an arithmetic number, because the mean of its divisors is an integer number (10000774815997).

Almost surely, 2^{20001549631993} is an apocalyptic number.

It is an amenable number.

20001549631993 is a deficient number, since it is larger than the sum of its proper divisors (1).

20001549631993 is an equidigital number, since it uses as much as digits as its factorization.

20001549631993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1574640, while the sum is 52.

The spelling of 20001549631993 in words is "twenty trillion, one billion, five hundred forty-nine million, six hundred thirty-one thousand, nine hundred ninety-three".