16217561121 has 4 divisors (see below), whose sum is σ = 21623414832. Its totient is φ = 10811707412.

The previous prime is 16217561099. The next prime is 16217561137. The reversal of 16217561121 is 12116571261.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16217561121 - 2¹¹ = 16217559073 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16217561021) 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, 2702926851 + ... + 2702926856.

It is an arithmetic number, because the mean of its divisors is an integer number (5405853708).

Almost surely, 2^16217561121 is an apocalyptic number.

It is an amenable number.

16217561121 is a deficient number, since it is larger than the sum of its proper divisors (5405853711).

16217561121 is an equidigital number, since it uses as much as digits as its factorization.

16217561121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5405853710.

The product of its digits is 5040, while the sum is 33.

The spelling of 16217561121 in words is "sixteen billion, two hundred seventeen million, five hundred sixty-one thousand, one hundred twenty-one".