16531884778729 has 2 divisors, whose sum is σ = 16531884778730. Its totient is φ = 16531884778728.

The previous prime is 16531884778711. The next prime is 16531884778753. The reversal of 16531884778729 is 92787748813561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11338864186329 + 5193020592400 = 3367323^2 + 2278820^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16531884778729 is a prime.

It is not a weakly prime, because it can be changed into another prime (16531887778729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8265942389364 + 8265942389365.

It is an arithmetic number, because the mean of its divisors is an integer number (8265942389365).

Almost surely, 2^{16531884778729} is an apocalyptic number.

It is an amenable number.

16531884778729 is a deficient number, since it is larger than the sum of its proper divisors (1).

16531884778729 is an equidigital number, since it uses as much as digits as its factorization.

16531884778729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1137991680, while the sum is 76.

The spelling of 16531884778729 in words is "sixteen trillion, five hundred thirty-one billion, eight hundred eighty-four million, seven hundred seventy-eight thousand, seven hundred twenty-nine".