18973557 has 12 divisors (see below), whose sum is σ = 27678924. Its totient is φ = 12523200.

The previous prime is 18973553. The next prime is 18973573. The reversal of 18973557 is 75537981.

18973557 is a `hidden beast` number, since 1 + 8 + 97 + 3 + 557 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 13242321 + 5731236 = 3639^2 + 2394^2 .

It is not a de Polignac number, because 18973557 - 2² = 18973553 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18973553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9528 + ... + 11345.

It is an arithmetic number, because the mean of its divisors is an integer number (2306577).

Almost surely, 2^18973557 is an apocalyptic number.

It is an amenable number.

18973557 is a deficient number, since it is larger than the sum of its proper divisors (8705367).

18973557 is a wasteful number, since it uses less digits than its factorization.

18973557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20980 (or 20977 counting only the distinct ones).

The product of its digits is 264600, while the sum is 45.

The square root of 18973557 is about 4355.8646673192. The cubic root of 18973557 is about 266.7163169704.

The spelling of 18973557 in words is "eighteen million, nine hundred seventy-three thousand, five hundred fifty-seven".