18987401 has 4 divisors (see below), whose sum is σ = 19500612. Its totient is φ = 18474192.

The previous prime is 18987391. The next prime is 18987457. The reversal of 18987401 is 10478981.

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

It can be written as a sum of positive squares in 2 ways, for example, as 7590025 + 11397376 = 2755^2 + 3376^2 .

It is a cyclic number.

It is not a de Polignac number, because 18987401 - 2⁶ = 18987337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18987481) 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 in 3 ways as a sum of consecutive naturals, for example, 256550 + ... + 256623.

It is an arithmetic number, because the mean of its divisors is an integer number (4875153).

Almost surely, 2^18987401 is an apocalyptic number.

It is an amenable number.

18987401 is a deficient number, since it is larger than the sum of its proper divisors (513211).

18987401 is an equidigital number, since it uses as much as digits as its factorization.

18987401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 513210.

The product of its (nonzero) digits is 16128, while the sum is 38.

The square root of 18987401 is about 4357.4534994650. The cubic root of 18987401 is about 266.7811707913.

The spelling of 18987401 in words is "eighteen million, nine hundred eighty-seven thousand, four hundred one".