19889945 has 8 divisors (see below), whose sum is σ = 24195336. Its totient is φ = 15693696.

The previous prime is 19889939. The next prime is 19889953. The reversal of 19889945 is 54998891.

It can be written as a sum of positive squares in 4 ways, for example, as 976144 + 18913801 = 988^2 + 4349^2 .

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 19889945 - 2⁴ = 19889929 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26882 + ... + 27611.

It is an arithmetic number, because the mean of its divisors is an integer number (3024417).

Almost surely, 2^19889945 is an apocalyptic number.

It is an amenable number.

19889945 is a deficient number, since it is larger than the sum of its proper divisors (4305391).

19889945 is an equidigital number, since it uses as much as digits as its factorization.

19889945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54571.

The product of its digits is 933120, while the sum is 53.

The square root of 19889945 is about 4459.8144580240. The cubic root of 19889945 is about 270.9429535475.

The spelling of 19889945 in words is "nineteen million, eight hundred eighty-nine thousand, nine hundred forty-five".