18861397 has 8 divisors (see below), whose sum is σ = 19562040. Its totient is φ = 18164160.

The previous prime is 18861377. The next prime is 18861407. The reversal of 18861397 is 79316881.

It can be written as a sum of positive squares in 4 ways, for example, as 276676 + 18584721 = 526^2 + 4311^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 18861397 - 2¹¹ = 18859349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18861307) 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, 17247 + ... + 18307.

It is an arithmetic number, because the mean of its divisors is an integer number (2445255).

Almost surely, 2^18861397 is an apocalyptic number.

It is an amenable number.

18861397 is a deficient number, since it is larger than the sum of its proper divisors (700643).

18861397 is a wasteful number, since it uses less digits than its factorization.

18861397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1703.

The product of its digits is 72576, while the sum is 43.

The square root of 18861397 is about 4342.9709876995. The cubic root of 18861397 is about 266.1897236941.

The spelling of 18861397 in words is "eighteen million, eight hundred sixty-one thousand, three hundred ninety-seven".