16557557 has 4 divisors (see below), whose sum is σ = 16574796. Its totient is φ = 16540320.

The previous prime is 16557533. The next prime is 16557577. The reversal of 16557557 is 75575561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75575561 = 157 ⋅481373.

It can be written as a sum of positive squares in 2 ways, for example, as 11566801 + 4990756 = 3401^2 + 2234^2 .

It is a cyclic number.

It is not a de Polignac number, because 16557557 - 2¹⁸ = 16295413 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 (16557517) 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, 7088 + ... + 9129.

It is an arithmetic number, because the mean of its divisors is an integer number (4143699).

Almost surely, 2^16557557 is an apocalyptic number.

It is an amenable number.

16557557 is a deficient number, since it is larger than the sum of its proper divisors (17239).

16557557 is a wasteful number, since it uses less digits than its factorization.

16557557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17238.

The product of its digits is 183750, while the sum is 41.

The square root of 16557557 is about 4069.0978115548. The cubic root of 16557557 is about 254.8778448627.

The spelling of 16557557 in words is "sixteen million, five hundred fifty-seven thousand, five hundred fifty-seven".