18969887 has 4 divisors (see below), whose sum is σ = 18979296. Its totient is φ = 18960480.

The previous prime is 18969877. The next prime is 18969901. The reversal of 18969887 is 78896981.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 78896981 = 7817 ⋅10093.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18969887 is a prime.

It is a super-2 number, since 2×18969887² = 719713225585538, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18969817) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 314 + ... + 6167.

It is an arithmetic number, because the mean of its divisors is an integer number (4744824).

Almost surely, 2^18969887 is an apocalyptic number.

18969887 is a deficient number, since it is larger than the sum of its proper divisors (9409).

18969887 is an equidigital number, since it uses as much as digits as its factorization.

18969887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9408.

The product of its digits is 1741824, while the sum is 56.

The square root of 18969887 is about 4355.4433758229. The cubic root of 18969887 is about 266.6991191408.

The spelling of 18969887 in words is "eighteen million, nine hundred sixty-nine thousand, eight hundred eighty-seven".