18987101 has 4 divisors (see below), whose sum is σ = 21699552. Its totient is φ = 16274652.

The previous prime is 18987053. The next prime is 18987103. The reversal of 18987101 is 10178981.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18987101 - 2¹⁴ = 18970717 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18987103) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1356215 + ... + 1356228.

It is an arithmetic number, because the mean of its divisors is an integer number (5424888).

Almost surely, 2^18987101 is an apocalyptic number.

It is an amenable number.

18987101 is a deficient number, since it is larger than the sum of its proper divisors (2712451).

18987101 is an equidigital number, since it uses as much as digits as its factorization.

18987101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2712450.

The product of its (nonzero) digits is 4032, while the sum is 35.

The square root of 18987101 is about 4357.4190755538. The cubic root of 18987101 is about 266.7797657407.

The spelling of 18987101 in words is "eighteen million, nine hundred eighty-seven thousand, one hundred one".