18249397 has 4 divisors (see below), whose sum is σ = 18258316. Its totient is φ = 18240480.

The previous prime is 18249389. The next prime is 18249401. The reversal of 18249397 is 79394281.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 79394281 = 8627 ⋅9203.

It can be written as a sum of positive squares in 2 ways, for example, as 617796 + 17631601 = 786^2 + 4199^2 .

It is a cyclic number.

It is not a de Polignac number, because 18249397 - 2³ = 18249389 is a prime.

It is a super-3 number, since 3×18249397³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18249337) 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, 313 + ... + 6049.

It is an arithmetic number, because the mean of its divisors is an integer number (4564579).

Almost surely, 2^18249397 is an apocalyptic number.

It is an amenable number.

18249397 is a deficient number, since it is larger than the sum of its proper divisors (8919).

18249397 is an equidigital number, since it uses as much as digits as its factorization.

18249397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8918.

The product of its digits is 108864, while the sum is 43.

The square root of 18249397 is about 4271.9312962640. The cubic root of 18249397 is about 263.2789716694.

The spelling of 18249397 in words is "eighteen million, two hundred forty-nine thousand, three hundred ninety-seven".