18136973 has 4 divisors (see below), whose sum is σ = 18163548. Its totient is φ = 18110400.

The previous prime is 18136969. The next prime is 18136981. The reversal of 18136973 is 37963181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 37963181 = 97 ⋅391373.

It can be written as a sum of positive squares in 2 ways, for example, as 12482089 + 5654884 = 3533^2 + 2378^2 .

It is a cyclic number.

It is not a de Polignac number, because 18136973 - 2² = 18136969 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18136933) 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, 12236 + ... + 13637.

It is an arithmetic number, because the mean of its divisors is an integer number (4540887).

Almost surely, 2^18136973 is an apocalyptic number.

It is an amenable number.

18136973 is a deficient number, since it is larger than the sum of its proper divisors (26575).

18136973 is an equidigital number, since it uses as much as digits as its factorization.

18136973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26574.

The product of its digits is 27216, while the sum is 38.

The square root of 18136973 is about 4258.7525168763. The cubic root of 18136973 is about 262.7372210842.

The spelling of 18136973 in words is "eighteen million, one hundred thirty-six thousand, nine hundred seventy-three".