18987945 has 8 divisors (see below), whose sum is σ = 30380736. Its totient is φ = 10126896.

The previous prime is 18987937. The next prime is 18987959. The reversal of 18987945 is 54978981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18987945 - 2³ = 18987937 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 632917 + ... + 632946.

It is an arithmetic number, because the mean of its divisors is an integer number (3797592).

Almost surely, 2^18987945 is an apocalyptic number.

18987945 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18987945 is a deficient number, since it is larger than the sum of its proper divisors (11392791).

18987945 is a wasteful number, since it uses less digits than its factorization.

18987945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1265871.

The product of its digits is 725760, while the sum is 51.

The square root of 18987945 is about 4357.5159207971. The cubic root of 18987945 is about 266.7837185784.

The spelling of 18987945 in words is "eighteen million, nine hundred eighty-seven thousand, nine hundred forty-five".