16557641 has 4 divisors (see below), whose sum is σ = 16784532. Its totient is φ = 16330752.

The previous prime is 16557601. The next prime is 16557659. The reversal of 16557641 is 14675561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 14675561 = 359 ⋅40879.

It can be written as a sum of positive squares in 2 ways, for example, as 6451600 + 10106041 = 2540^2 + 3179^2 .

It is a cyclic number.

It is not a de Polignac number, because 16557641 - 2⁶ = 16557577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16557601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 113336 + ... + 113481.

It is an arithmetic number, because the mean of its divisors is an integer number (4196133).

Almost surely, 2^16557641 is an apocalyptic number.

It is an amenable number.

16557641 is a deficient number, since it is larger than the sum of its proper divisors (226891).

16557641 is an equidigital number, since it uses as much as digits as its factorization.

16557641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226890.

The product of its digits is 25200, while the sum is 35.

The square root of 16557641 is about 4069.1081332400. The cubic root of 16557641 is about 254.8782758784.

The spelling of 16557641 in words is "sixteen million, five hundred fifty-seven thousand, six hundred forty-one".