18378949 has 4 divisors (see below), whose sum is σ = 18447040. Its totient is φ = 18310860.

The previous prime is 18378937. The next prime is 18378959. The reversal of 18378949 is 94987381.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18378949 - 2⁷ = 18378821 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 (18378929) 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, 33639 + ... + 34180.

It is an arithmetic number, because the mean of its divisors is an integer number (4611760).

Almost surely, 2^18378949 is an apocalyptic number.

It is an amenable number.

18378949 is a deficient number, since it is larger than the sum of its proper divisors (68091).

18378949 is an equidigital number, since it uses as much as digits as its factorization.

18378949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68090.

The product of its digits is 435456, while the sum is 49.

The square root of 18378949 is about 4287.0676458391. The cubic root of 18378949 is about 263.9005067773.

The spelling of 18378949 in words is "eighteen million, three hundred seventy-eight thousand, nine hundred forty-nine".