16545661 has 16 divisors (see below), whose sum is σ = 18832896. Its totient is φ = 14520000.

The previous prime is 16545649. The next prime is 16545679. The reversal of 16545661 is 16654561.

It is a happy number.

It is not a de Polignac number, because 16545661 - 2⁵ = 16545629 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 (16545601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41061 + ... + 41461.

It is an arithmetic number, because the mean of its divisors is an integer number (1177056).

Almost surely, 2^16545661 is an apocalyptic number.

16545661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16545661 is a deficient number, since it is larger than the sum of its proper divisors (2287235).

16545661 is an equidigital number, since it uses as much as digits as its factorization.

16545661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 465 (or 443 counting only the distinct ones).

The product of its digits is 21600, while the sum is 34.

The square root of 16545661 is about 4067.6357998228. The cubic root of 16545661 is about 254.8167900975.

Subtracting 16545661 from its reverse (16654561), we obtain a square (108900 = 330²).

The spelling of 16545661 in words is "sixteen million, five hundred forty-five thousand, six hundred sixty-one".