16561161 has 12 divisors (see below), whose sum is σ = 24693760. Its totient is φ = 10684440.

The previous prime is 16561157. The next prime is 16561169. The reversal of 16561161 is 16116561.

16561161 is a `hidden beast` number, since 1 + 656 + 1 + 1 + 6 + 1 = 666.

16561161 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 16561161 - 2² = 16561157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16561169) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 29401 + ... + 29958.

Almost surely, 2^16561161 is an apocalyptic number.

It is an amenable number.

16561161 is a deficient number, since it is larger than the sum of its proper divisors (8132599).

16561161 is a wasteful number, since it uses less digits than its factorization.

16561161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59396 (or 59393 counting only the distinct ones).

The product of its digits is 1080, while the sum is 27.

The square root of 16561161 is about 4069.5406374676. The cubic root of 16561161 is about 254.8963361798.

The spelling of 16561161 in words is "sixteen million, five hundred sixty-one thousand, one hundred sixty-one".