18212378 has 4 divisors (see below), whose sum is σ = 27318570. Its totient is φ = 9106188.

The previous prime is 18212371. The next prime is 18212387. The reversal of 18212378 is 87321281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87321281 = 9257 ⋅9433.

It can be written as a sum of positive squares in only one way, i.e., 13446889 + 4765489 = 3667^2 + 2183^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18212371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4553093 + ... + 4553096.

Almost surely, 2^18212378 is an apocalyptic number.

18212378 is a deficient number, since it is larger than the sum of its proper divisors (9106192).

18212378 is an equidigital number, since it uses as much as digits as its factorization.

18212378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9106191.

The product of its digits is 5376, while the sum is 32.

The square root of 18212378 is about 4267.5962789374. The cubic root of 18212378 is about 263.1008302246.

The spelling of 18212378 in words is "eighteen million, two hundred twelve thousand, three hundred seventy-eight".