19681489 has 4 divisors (see below), whose sum is σ = 19730020. Its totient is φ = 19632960.

The previous prime is 19681483. The next prime is 19681499. The reversal of 19681489 is 98418691.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98418691 = 7 ⋅14059813.

It can be written as a sum of positive squares in 2 ways, for example, as 16321600 + 3359889 = 4040^2 + 1833^2 .

It is a cyclic number.

It is not a de Polignac number, because 19681489 - 2⁹ = 19680977 is a prime.

It is a super-2 number, since 2×19681489² = 774722018514242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19681483) 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, 23652 + ... + 24469.

It is an arithmetic number, because the mean of its divisors is an integer number (4932505).

Almost surely, 2^19681489 is an apocalyptic number.

It is an amenable number.

19681489 is a deficient number, since it is larger than the sum of its proper divisors (48531).

19681489 is an equidigital number, since it uses as much as digits as its factorization.

19681489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48530.

The product of its digits is 124416, while the sum is 46.

The square root of 19681489 is about 4436.3824226502. The cubic root of 19681489 is about 269.9930908154.

The spelling of 19681489 in words is "nineteen million, six hundred eighty-one thousand, four hundred eighty-nine".