20919188985 has 32 divisors (see below), whose sum is σ = 33859119360. Its totient is φ = 11027923200.

The previous prime is 20919188977. The next prime is 20919188989. The reversal of 20919188985 is 58988191902.

It is not a de Polignac number, because 20919188985 - 2³ = 20919188977 is a prime.

It is a super-2 number, since 2×20919188985² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20919188989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 673140 + ... + 703530.

It is an arithmetic number, because the mean of its divisors is an integer number (1058097480).

Almost surely, 2^20919188985 is an apocalyptic number.

It is an amenable number.

20919188985 is a deficient number, since it is larger than the sum of its proper divisors (12939930375).

20919188985 is a wasteful number, since it uses less digits than its factorization.

20919188985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30929.

The product of its (nonzero) digits is 3732480, while the sum is 60.

The spelling of 20919188985 in words is "twenty billion, nine hundred nineteen million, one hundred eighty-eight thousand, nine hundred eighty-five".