18445861 has 8 divisors (see below), whose sum is σ = 21248000. Its totient is φ = 15685488.

The previous prime is 18445853. The next prime is 18445877. The reversal of 18445861 is 16854481.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18445861 - 2³ = 18445853 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18445861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18445841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9486 + ... + 11263.

It is an arithmetic number, because the mean of its divisors is an integer number (2656000).

Almost surely, 2^18445861 is an apocalyptic number.

It is an amenable number.

18445861 is a deficient number, since it is larger than the sum of its proper divisors (2802139).

18445861 is a wasteful number, since it uses less digits than its factorization.

18445861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20883.

The product of its digits is 30720, while the sum is 37.

The square root of 18445861 is about 4294.8644914595. The cubic root of 18445861 is about 264.2203786178.

It can be divided in two parts, 18445 and 861, that added together give a triangular number (19306 = T₁₉₆).

The spelling of 18445861 in words is "eighteen million, four hundred forty-five thousand, eight hundred sixty-one".