16220844855121 has 3 divisors (see below), whose sum is σ = 16220848882633. Its totient is φ = 16220840827610.

The previous prime is 16220844855073. The next prime is 16220844855181. The reversal of 16220844855121 is 12155844802261.

The square root of 16220844855121 is 4027511.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 16220844855121 - 2¹⁹ = 16220844330833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16220844855181) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2013756 + ... + 6041266.

Almost surely, 2^{16220844855121} is an apocalyptic number.

16220844855121 is the 4027511-st square number.

16220844855121 is the 2013756-th centered octagonal number.

It is an amenable number.

16220844855121 is a deficient number, since it is larger than the sum of its proper divisors (4027512).

16220844855121 is an frugal number, since it uses more digits than its factorization.

16220844855121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8055022 (or 4027511 counting only the distinct ones).

The product of its (nonzero) digits is 1228800, while the sum is 49.

Multiplying 16220844855121 by its sum of digits (49), we get a square (794821397900929 = 28192577²).

The spelling of 16220844855121 in words is "sixteen trillion, two hundred twenty billion, eight hundred forty-four million, eight hundred fifty-five thousand, one hundred twenty-one".