21919667675491 has 4 divisors (see below), whose sum is σ = 21921247257552. Its totient is φ = 21918088093432.

The previous prime is 21919667675467. The next prime is 21919667675531. The reversal of 21919667675491 is 19457676691912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21919667675491 - 2²¹ = 21919665578339 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21919667675291) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 789770215 + ... + 789797968.

It is an arithmetic number, because the mean of its divisors is an integer number (5480311814388).

Almost surely, 2^{21919667675491} is an apocalyptic number.

21919667675491 is a deficient number, since it is larger than the sum of its proper divisors (1579582061).

21919667675491 is a wasteful number, since it uses less digits than its factorization.

21919667675491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1579582060.

The product of its digits is 308629440, while the sum is 73.

The spelling of 21919667675491 in words is "twenty-one trillion, nine hundred nineteen billion, six hundred sixty-seven million, six hundred seventy-five thousand, four hundred ninety-one".