21719205591 has 8 divisors (see below), whose sum is σ = 29118935664. Its totient is φ = 14399472960.

The previous prime is 21719205583. The next prime is 21719205617. The reversal of 21719205591 is 19550291712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21719205591 - 2³ = 21719205583 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21719205581) 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 7 ways as a sum of consecutive naturals, for example, 19998726 + ... + 19999811.

It is an arithmetic number, because the mean of its divisors is an integer number (3639866958).

Almost surely, 2^21719205591 is an apocalyptic number.

21719205591 is a deficient number, since it is larger than the sum of its proper divisors (7399730073).

21719205591 is a wasteful number, since it uses less digits than its factorization.

21719205591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39998721.

The product of its (nonzero) digits is 56700, while the sum is 42.

The spelling of 21719205591 in words is "twenty-one billion, seven hundred nineteen million, two hundred five thousand, five hundred ninety-one".