18747397 has 4 divisors (see below), whose sum is σ = 18756076. Its totient is φ = 18738720.

The previous prime is 18747389. The next prime is 18747403. The reversal of 18747397 is 79374781.

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: 79374781 = 109 ⋅728209.

It can be written as a sum of positive squares in 2 ways, for example, as 8288641 + 10458756 = 2879^2 + 3234^2 .

It is a cyclic number.

It is not a de Polignac number, because 18747397 - 2³ = 18747389 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 (18741397) 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, 1747 + ... + 6367.

It is an arithmetic number, because the mean of its divisors is an integer number (4689019).

Almost surely, 2^18747397 is an apocalyptic number.

It is an amenable number.

18747397 is a deficient number, since it is larger than the sum of its proper divisors (8679).

18747397 is an equidigital number, since it uses as much as digits as its factorization.

18747397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8678.

The product of its digits is 296352, while the sum is 46.

The square root of 18747397 is about 4329.8264399396. The cubic root of 18747397 is about 265.6523479478.

The spelling of 18747397 in words is "eighteen million, seven hundred forty-seven thousand, three hundred ninety-seven".