18978345 has 12 divisors (see below), whose sum is σ = 32895876. Its totient is φ = 10121760.

The previous prime is 18978329. The next prime is 18978403. The reversal of 18978345 is 54387981.

It can be written as a sum of positive squares in 2 ways, for example, as 9960336 + 9018009 = 3156^2 + 3003^2 .

It is not a de Polignac number, because 18978345 - 2⁴ = 18978329 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 421741 = 18978345 / (1 + 8 + 9 + 7 + 8 + 3 + 4 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 18978345.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 210826 + ... + 210915.

It is an arithmetic number, because the mean of its divisors is an integer number (2741323).

Almost surely, 2^18978345 is an apocalyptic number.

18978345 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18978345 is a deficient number, since it is larger than the sum of its proper divisors (13917531).

18978345 is a wasteful number, since it uses less digits than its factorization.

18978345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421752 (or 421749 counting only the distinct ones).

The product of its digits is 241920, while the sum is 45.

The square root of 18978345 is about 4356.4142365023. The cubic root of 18978345 is about 266.7387504782.

The spelling of 18978345 in words is "eighteen million, nine hundred seventy-eight thousand, three hundred forty-five".