18131207 has 4 divisors (see below), whose sum is σ = 18174696. Its totient is φ = 18087720.

The previous prime is 18131203. The next prime is 18131209. The reversal of 18131207 is 70213181.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18131207 - 2² = 18131203 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 (18131203) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21113 + ... + 21954.

It is an arithmetic number, because the mean of its divisors is an integer number (4543674).

Almost surely, 2^18131207 is an apocalyptic number.

18131207 is a deficient number, since it is larger than the sum of its proper divisors (43489).

18131207 is an equidigital number, since it uses as much as digits as its factorization.

18131207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43488.

The product of its (nonzero) digits is 336, while the sum is 23.

The square root of 18131207 is about 4258.0755042625. The cubic root of 18131207 is about 262.7093755081.

Adding to 18131207 its reverse (70213181), we get a palindrome (88344388).

The spelling of 18131207 in words is "eighteen million, one hundred thirty-one thousand, two hundred seven".