20919986109 has 24 divisors (see below), whose sum is σ = 32974718400. Its totient is φ = 12674975040.

The previous prime is 20919986071. The next prime is 20919986137. The reversal of 20919986109 is 90168991902.

20919986109 is a `hidden beast` number, since 2 + 0 + 9 + 19 + 9 + 8 + 610 + 9 = 666.

It is not a de Polignac number, because 20919986109 - 2⁷ = 20919985981 is a prime.

It is a super-3 number, since 3×20919986109³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20919986209) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 319432 + ... + 379310.

It is an arithmetic number, because the mean of its divisors is an integer number (1373946600).

Almost surely, 2^20919986109 is an apocalyptic number.

It is an amenable number.

20919986109 is a deficient number, since it is larger than the sum of its proper divisors (12054732291).

20919986109 is a wasteful number, since it uses less digits than its factorization.

20919986109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63425 (or 63422 counting only the distinct ones).

The product of its (nonzero) digits is 629856, while the sum is 54.

The spelling of 20919986109 in words is "twenty billion, nine hundred nineteen million, nine hundred eighty-six thousand, one hundred nine".