18146978 has 4 divisors (see below), whose sum is σ = 27220470. Its totient is φ = 9073488.

The previous prime is 18146971. The next prime is 18146981. The reversal of 18146978 is 87964181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87964181 = 389 ⋅226129.

It can be written as a sum of positive squares in only one way, i.e., 12159169 + 5987809 = 3487^2 + 2447^2 .

It is not an unprimeable number, because it can be changed into a prime (18146971) 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 as a sum of consecutive naturals, namely, 4536743 + ... + 4536746.

Almost surely, 2^18146978 is an apocalyptic number.

18146978 is a deficient number, since it is larger than the sum of its proper divisors (9073492).

18146978 is an equidigital number, since it uses as much as digits as its factorization.

18146978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9073491.

The product of its digits is 96768, while the sum is 44.

The square root of 18146978 is about 4259.9269946796. The cubic root of 18146978 is about 262.7855239384.

The spelling of 18146978 in words is "eighteen million, one hundred forty-six thousand, nine hundred seventy-eight".