16345548161221 has 4 divisors (see below), whose sum is σ = 17307050994252. Its totient is φ = 15384045328192.

The previous prime is 16345548161191. The next prime is 16345548161263. The reversal of 16345548161221 is 12216184554361.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7001919300996 + 9343628860225 = 2646114^2 + 3056735^2 .

It is a cyclic number.

It is not a de Polignac number, because 16345548161221 - 2⁷ = 16345548161093 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16345548161821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 480751416490 + ... + 480751416523.

It is an arithmetic number, because the mean of its divisors is an integer number (4326762748563).

Almost surely, 2^{16345548161221} is an apocalyptic number.

It is an amenable number.

16345548161221 is a deficient number, since it is larger than the sum of its proper divisors (961502833031).

16345548161221 is an equidigital number, since it uses as much as digits as its factorization.

16345548161221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 961502833030.

The product of its digits is 1382400, while the sum is 49.

The spelling of 16345548161221 in words is "sixteen trillion, three hundred forty-five billion, five hundred forty-eight million, one hundred sixty-one thousand, two hundred twenty-one".