18891889 has 8 divisors (see below), whose sum is σ = 19300680. Its totient is φ = 18487296.

The previous prime is 18891881. The next prime is 18891919. The reversal of 18891889 is 98819881.

It can be written as a sum of positive squares in 4 ways, for example, as 3744225 + 15147664 = 1935^2 + 3892^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18891889 - 2³ = 18891881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18891881) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9057 + ... + 10945.

It is an arithmetic number, because the mean of its divisors is an integer number (2412585).

Almost surely, 2^18891889 is an apocalyptic number.

It is an amenable number.

18891889 is a deficient number, since it is larger than the sum of its proper divisors (408791).

18891889 is a wasteful number, since it uses less digits than its factorization.

18891889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2099.

The product of its digits is 331776, while the sum is 52.

The square root of 18891889 is about 4346.4800701257. The cubic root of 18891889 is about 266.3330903650. Note that the first 3 decimals are identical.

The spelling of 18891889 in words is "eighteen million, eight hundred ninety-one thousand, eight hundred eighty-nine".