18278946 has 72 divisors (see below), whose sum is σ = 47236800. Its totient is φ = 5196312.

The previous prime is 18278899. The next prime is 18278947. The reversal of 18278946 is 64987281.

It is not an unprimeable number, because it can be changed into a prime (18278947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 91755 + ... + 91953.

Almost surely, 2^18278946 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18278946, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23618400).

18278946 is an abundant number, since it is smaller than the sum of its proper divisors (28957854).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18278946 is an frugal number, since it uses more digits than its factorization.

18278946 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232 (or 211 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 18278946 is about 4275.3884034085. The cubic root of 18278946 is about 263.4209934440.

The spelling of 18278946 in words is "eighteen million, two hundred seventy-eight thousand, nine hundred forty-six".