18055557 has 12 divisors (see below), whose sum is σ = 28086604. Its totient is φ = 11111040.

The previous prime is 18055553. The next prime is 18055561. The reversal of 18055557 is 75555081.

It is an interprime number because it is at equal distance from previous prime (18055553) and next prime (18055561).

It can be written as a sum of positive squares in 2 ways, for example, as 1846881 + 16208676 = 1359^2 + 4026^2 .

It is not a de Polignac number, because 18055557 - 2² = 18055553 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18055553) 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, 77044 + ... + 77277.

Almost surely, 2^18055557 is an apocalyptic number.

It is an amenable number.

18055557 is a deficient number, since it is larger than the sum of its proper divisors (10031047).

18055557 is a wasteful number, since it uses less digits than its factorization.

18055557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154340 (or 154337 counting only the distinct ones).

The product of its (nonzero) digits is 35000, while the sum is 36.

The square root of 18055557 is about 4249.1830979613. The cubic root of 18055557 is about 262.3434931011.

The spelling of 18055557 in words is "eighteen million, fifty-five thousand, five hundred fifty-seven".