20491889508 has 36 divisors (see below), whose sum is σ = 51803763648. Its totient is φ = 6829994160.

The previous prime is 20491889501. The next prime is 20491889513. The reversal of 20491889508 is 80598819402.

20491889508 is a `hidden beast` number, since 2 + 0 + 49 + 18 + 89 + 508 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (20491889501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 520393 + ... + 558383.

Almost surely, 2^20491889508 is an apocalyptic number.

It is an amenable number.

20491889508 is an abundant number, since it is smaller than the sum of its proper divisors (31311874140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20491889508 is a wasteful number, since it uses less digits than its factorization.

20491889508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52984 (or 52979 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 54.

The spelling of 20491889508 in words is "twenty billion, four hundred ninety-one million, eight hundred eighty-nine thousand, five hundred eight".