19998889 has 4 divisors (see below), whose sum is σ = 20008080. Its totient is φ = 19989700.

The previous prime is 19998877. The next prime is 19998899. The reversal of 19998889 is 98889991.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 19998889 - 2¹³ = 19990697 is a prime.

It is a super-2 number, since 2×19998889² = 799911122468642, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19998809) 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, 714 + ... + 6364.

It is an arithmetic number, because the mean of its divisors is an integer number (5002020).

Almost surely, 2^19998889 is an apocalyptic number.

It is an amenable number.

19998889 is a deficient number, since it is larger than the sum of its proper divisors (9191).

19998889 is an equidigital number, since it uses as much as digits as its factorization.

19998889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9190.

The product of its digits is 3359232, while the sum is 61.

The square root of 19998889 is about 4472.0117396984. The cubic root of 19998889 is about 271.4367353698.

The spelling of 19998889 in words is "nineteen million, nine hundred ninety-eight thousand, eight hundred eighty-nine".