16561226217 has 8 divisors (see below), whose sum is σ = 22083606496. Its totient is φ = 11039831712.

The previous prime is 16561226203. The next prime is 16561226239. The reversal of 16561226217 is 71262216561.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 16561226217 - 2²⁴ = 16544449001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16561226257) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 206308 + ... + 275109.

It is an arithmetic number, because the mean of its divisors is an integer number (2760450812).

Almost surely, 2^16561226217 is an apocalyptic number.

It is an amenable number.

16561226217 is a deficient number, since it is larger than the sum of its proper divisors (5522380279).

16561226217 is a wasteful number, since it uses less digits than its factorization.

16561226217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 492887.

The product of its digits is 60480, while the sum is 39.

The spelling of 16561226217 in words is "sixteen billion, five hundred sixty-one million, two hundred twenty-six thousand, two hundred seventeen".