19901188616 has 8 divisors (see below), whose sum is σ = 37314728670. Its totient is φ = 9950594304.

The previous prime is 19901188609. The next prime is 19901188649. The reversal of 19901188616 is 61688110991.

It can be written as a sum of positive squares in only one way, i.e., 18266603716 + 1634584900 = 135154^2 + 40430^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1243824281 + ... + 1243824296.

Almost surely, 2^19901188616 is an apocalyptic number.

It is an amenable number.

19901188616 is a deficient number, since it is larger than the sum of its proper divisors (17413540054).

19901188616 is a wasteful number, since it uses less digits than its factorization.

19901188616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2487648583 (or 2487648579 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 50.

The spelling of 19901188616 in words is "nineteen billion, nine hundred one million, one hundred eighty-eight thousand, six hundred sixteen".