21991619912 has 16 divisors (see below), whose sum is σ = 41240427900. Its totient is φ = 10994172480.

The previous prime is 21991619873. The next prime is 21991619921.

21991619912 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 2 ways, for example, as 21058072996 + 933546916 = 145114^2 + 30554^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 146639 + ... + 255902.

Almost surely, 2^21991619912 is an apocalyptic number.

It is an amenable number.

21991619912 is a deficient number, since it is larger than the sum of its proper divisors (19248807988).

21991619912 is a wasteful number, since it uses less digits than its factorization.

21991619912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 409376 (or 409372 counting only the distinct ones).

The product of its digits is 157464, while the sum is 50.

The spelling of 21991619912 in words is "twenty-one billion, nine hundred ninety-one million, six hundred nineteen thousand, nine hundred twelve".