18867861 has 6 divisors (see below), whose sum is σ = 27253590. Its totient is φ = 12578568.

The previous prime is 18867859. The next prime is 18867869. The reversal of 18867861 is 16876881.

It can be written as a sum of positive squares in only one way, i.e., 18404100 + 463761 = 4290^2 + 681^2 .

It is not a de Polignac number, because 18867861 - 2¹ = 18867859 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18867869) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1048206 + ... + 1048223.

It is an arithmetic number, because the mean of its divisors is an integer number (4542265).

Almost surely, 2^18867861 is an apocalyptic number.

It is an amenable number.

18867861 is a deficient number, since it is larger than the sum of its proper divisors (8385729).

18867861 is a wasteful number, since it uses less digits than its factorization.

18867861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2096435 (or 2096432 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 18867861 is about 4343.7151149678. The cubic root of 18867861 is about 266.2201288977.

The spelling of 18867861 in words is "eighteen million, eight hundred sixty-seven thousand, eight hundred sixty-one".