21691299764167 has 8 divisors (see below), whose sum is σ = 23663315834640. Its totient is φ = 19719296981760.

The previous prime is 21691299764159. The next prime is 21691299764179. The reversal of 21691299764167 is 76146799219612.

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

It is a cyclic number.

It is not a de Polignac number, because 21691299764167 - 2³ = 21691299764159 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21691299764096 and 21691299764105.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21691299764567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 259009 + ... + 6591637.

It is an arithmetic number, because the mean of its divisors is an integer number (2957914479330).

Almost surely, 2^{21691299764167} is an apocalyptic number.

21691299764167 is a deficient number, since it is larger than the sum of its proper divisors (1972016070473).

21691299764167 is a wasteful number, since it uses less digits than its factorization.

21691299764167 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6644033.

The product of its digits is 123451776, while the sum is 70.

Subtracting 21691299764167 from its reverse (76146799219612), we obtain a palindrome (54455499455445).

The spelling of 21691299764167 in words is "twenty-one trillion, six hundred ninety-one billion, two hundred ninety-nine million, seven hundred sixty-four thousand, one hundred sixty-seven".