16771561 has 4 divisors (see below), whose sum is σ = 16973712. Its totient is φ = 16569412.

The previous prime is 16771481. The next prime is 16771609. The reversal of 16771561 is 16517761.

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 16771561 - 2¹¹ = 16769513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16771361) 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, 100951 + ... + 101116.

It is an arithmetic number, because the mean of its divisors is an integer number (4243428).

Almost surely, 2^16771561 is an apocalyptic number.

It is an amenable number.

16771561 is a deficient number, since it is larger than the sum of its proper divisors (202151).

16771561 is an equidigital number, since it uses as much as digits as its factorization.

16771561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202150.

The product of its digits is 8820, while the sum is 34.

The square root of 16771561 is about 4095.3096342035. The cubic root of 16771561 is about 255.9712339504.

The spelling of 16771561 in words is "sixteen million, seven hundred seventy-one thousand, five hundred sixty-one".