21647109728969 has 4 divisors (see below), whose sum is σ = 21707408085120. Its totient is φ = 21586811372820.

The previous prime is 21647109728963. The next prime is 21647109728983. The reversal of 21647109728969 is 96982790174612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21647109728969 is a prime.

It is a super-2 number, since 2×21647109728969² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21647109728963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30149177537 + ... + 30149178254.

It is an arithmetic number, because the mean of its divisors is an integer number (5426852021280).

Almost surely, 2^{21647109728969} is an apocalyptic number.

It is an amenable number.

21647109728969 is a deficient number, since it is larger than the sum of its proper divisors (60298356151).

21647109728969 is an equidigital number, since it uses as much as digits as its factorization.

21647109728969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60298356150.

The product of its (nonzero) digits is 164602368, while the sum is 71.

The spelling of 21647109728969 in words is "twenty-one trillion, six hundred forty-seven billion, one hundred nine million, seven hundred twenty-eight thousand, nine hundred sixty-nine".