21721772195999 has 4 divisors (see below), whose sum is σ = 22999523501664. Its totient is φ = 20444020890336.

The previous prime is 21721772195983. The next prime is 21721772196013. The reversal of 21721772195999 is 99959127712712.

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 21721772195999 - 2⁴ = 21721772195983 is a prime.

It is a super-3 number, since 3×21721772195999³ (a number of 41 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21721772195939) 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, 638875652807 + ... + 638875652840.

It is an arithmetic number, because the mean of its divisors is an integer number (5749880875416).

Almost surely, 2^{21721772195999} is an apocalyptic number.

21721772195999 is a deficient number, since it is larger than the sum of its proper divisors (1277751305665).

21721772195999 is a wasteful number, since it uses less digits than its factorization.

21721772195999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1277751305664.

The product of its digits is 90016920, while the sum is 71.

The spelling of 21721772195999 in words is "twenty-one trillion, seven hundred twenty-one billion, seven hundred seventy-two million, one hundred ninety-five thousand, nine hundred ninety-nine".