19891812104 has 8 divisors (see below), whose sum is σ = 37297147710. Its totient is φ = 9945906048.

The previous prime is 19891812103. The next prime is 19891812137. The reversal of 19891812104 is 40121819891.

It can be written as a sum of positive squares in only one way, i.e., 14399520004 + 5492292100 = 119998^2 + 74110^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (19891812103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1243238249 + ... + 1243238264.

Almost surely, 2^19891812104 is an apocalyptic number.

It is an amenable number.

19891812104 is a deficient number, since it is larger than the sum of its proper divisors (17405335606).

19891812104 is a wasteful number, since it uses less digits than its factorization.

19891812104 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2486476519 (or 2486476515 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 44.

The spelling of 19891812104 in words is "nineteen billion, eight hundred ninety-one million, eight hundred twelve thousand, one hundred four".