21872266471765 has 4 divisors (see below), whose sum is σ = 26246719766124. Its totient is φ = 17497813177408.

The previous prime is 21872266471691. The next prime is 21872266471771. The reversal of 21872266471765 is 56717466227812.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13140436500676 + 8731829971089 = 3624974^2 + 2954967^2 .

It is a cyclic number.

It is not a de Polignac number, because 21872266471765 - 2²¹ = 21872264374613 is a prime.

It is a super-2 number, since 2×21872266471765² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21872266471697 and 21872266471706.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2187226647172 + ... + 2187226647181.

It is an arithmetic number, because the mean of its divisors is an integer number (6561679941531).

Almost surely, 2^{21872266471765} is an apocalyptic number.

It is an amenable number.

21872266471765 is a deficient number, since it is larger than the sum of its proper divisors (4374453294359).

21872266471765 is an equidigital number, since it uses as much as digits as its factorization.

21872266471765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4374453294358.

The product of its digits is 94832640, while the sum is 64.

The spelling of 21872266471765 in words is "twenty-one trillion, eight hundred seventy-two billion, two hundred sixty-six million, four hundred seventy-one thousand, seven hundred sixty-five".