18861645 has 32 divisors (see below), whose sum is σ = 33361920. Its totient is φ = 9023040.

The previous prime is 18861643. The next prime is 18861673. The reversal of 18861645 is 54616881.

It is not a de Polignac number, because 18861645 - 2¹ = 18861643 is a prime.

It is a super-3 number, since 3×18861645³ (a number of 23 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18861643) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12312 + ... + 13758.

It is an arithmetic number, because the mean of its divisors is an integer number (1042560).

Almost surely, 2^18861645 is an apocalyptic number.

18861645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18861645 is a deficient number, since it is larger than the sum of its proper divisors (14500275).

18861645 is a wasteful number, since it uses less digits than its factorization.

18861645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1545.

The product of its digits is 46080, while the sum is 39.

The square root of 18861645 is about 4342.9995394888. Note that the first 3 decimals coincide. The cubic root of 18861645 is about 266.1908903585.

The spelling of 18861645 in words is "eighteen million, eight hundred sixty-one thousand, six hundred forty-five".