18881197 has 8 divisors (see below), whose sum is σ = 19708920. Its totient is φ = 18071040.

The previous prime is 18881173. The next prime is 18881209. The reversal of 18881197 is 79118881.

It can be written as a sum of positive squares in 4 ways, for example, as 3663396 + 15217801 = 1914^2 + 3901^2 .

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 18881197 - 2¹⁹ = 18356909 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 (18881167) 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, 2172 + ... + 6517.

It is an arithmetic number, because the mean of its divisors is an integer number (2463615).

Almost surely, 2^18881197 is an apocalyptic number.

18881197 is the 2173-rd decagonal number.

It is an amenable number.

18881197 is a deficient number, since it is larger than the sum of its proper divisors (827723).

18881197 is an equidigital number, since it uses as much as digits as its factorization.

18881197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8783.

The product of its digits is 32256, while the sum is 43.

The square root of 18881197 is about 4345.2499352741. The cubic root of 18881197 is about 266.2828365094.

The spelling of 18881197 in words is "eighteen million, eight hundred eighty-one thousand, one hundred ninety-seven".