18987898 has 4 divisors (see below), whose sum is σ = 28481850. Its totient is φ = 9493948.

The previous prime is 18987889. The next prime is 18987907. The reversal of 18987898 is 89878981.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (18987889) and next prime (18987907).

It can be written as a sum of positive squares in only one way, i.e., 15737089 + 3250809 = 3967^2 + 1803^2 .

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4746973 + ... + 4746976.

Almost surely, 2^18987898 is an apocalyptic number.

18987898 is a deficient number, since it is larger than the sum of its proper divisors (9493952).

18987898 is an equidigital number, since it uses as much as digits as its factorization.

18987898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9493951.

The product of its digits is 2322432, while the sum is 58.

The square root of 18987898 is about 4357.5105278129. The cubic root of 18987898 is about 266.7834984590.

The spelling of 18987898 in words is "eighteen million, nine hundred eighty-seven thousand, eight hundred ninety-eight".