18987455 has 4 divisors (see below), whose sum is σ = 22784952. Its totient is φ = 15189960.

The previous prime is 18987391. The next prime is 18987457. The reversal of 18987455 is 55478981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 55478981 = 1213 ⋅45737.

It is not a de Polignac number, because 18987455 - 2⁶ = 18987391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18987457) 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, 1898741 + ... + 1898750.

It is an arithmetic number, because the mean of its divisors is an integer number (5696238).

Almost surely, 2^18987455 is an apocalyptic number.

18987455 is a deficient number, since it is larger than the sum of its proper divisors (3797497).

18987455 is an equidigital number, since it uses as much as digits as its factorization.

18987455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3797496.

The product of its digits is 403200, while the sum is 47.

The square root of 18987455 is about 4357.4596957402. The cubic root of 18987455 is about 266.7814236988.

The spelling of 18987455 in words is "eighteen million, nine hundred eighty-seven thousand, four hundred fifty-five".