21891942108 has 36 divisors (see below), whose sum is σ = 55381347840. Its totient is φ = 7291593216.

The previous prime is 21891942103. The next prime is 21891942197. The reversal of 21891942108 is 80124919812.

21891942108 is a `hidden beast` number, since 218 + 9 + 1 + 9 + 421 + 0 + 8 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21891942103) 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, 191685 + ... + 283772.

Almost surely, 2^21891942108 is an apocalyptic number.

It is an amenable number.

21891942108 is an abundant number, since it is smaller than the sum of its proper divisors (33489405732).

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

21891942108 is a wasteful number, since it uses less digits than its factorization.

21891942108 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 476746 (or 476741 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 45.

The spelling of 21891942108 in words is "twenty-one billion, eight hundred ninety-one million, nine hundred forty-two thousand, one hundred eight".