16542788031221 has 2 divisors, whose sum is σ = 16542788031222. Its totient is φ = 16542788031220.

The previous prime is 16542788031137. The next prime is 16542788031229. The reversal of 16542788031221 is 12213088724561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16382499100900 + 160288930321 = 4047530^2 + 400361^2 .

It is a cyclic number.

It is not a de Polignac number, because 16542788031221 - 2¹⁸ = 16542787769077 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 16542788031221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16542788031229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8271394015610 + 8271394015611.

It is an arithmetic number, because the mean of its divisors is an integer number (8271394015611).

Almost surely, 2^{16542788031221} is an apocalyptic number.

It is an amenable number.

16542788031221 is a deficient number, since it is larger than the sum of its proper divisors (1).

16542788031221 is an equidigital number, since it uses as much as digits as its factorization.

16542788031221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1290240, while the sum is 50.

The spelling of 16542788031221 in words is "sixteen trillion, five hundred forty-two billion, seven hundred eighty-eight million, thirty-one thousand, two hundred twenty-one".