21789277665 has 8 divisors (see below), whose sum is σ = 34862844288. Its totient is φ = 11620948080.

The previous prime is 21789277607. The next prime is 21789277673. The reversal of 21789277665 is 56677298712.

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

It is not a de Polignac number, because 21789277665 - 2⁷ = 21789277537 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21789277599 and 21789277608.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 726309241 + ... + 726309270.

It is an arithmetic number, because the mean of its divisors is an integer number (4357855536).

Almost surely, 2^21789277665 is an apocalyptic number.

It is an amenable number.

21789277665 is a deficient number, since it is larger than the sum of its proper divisors (13073566623).

21789277665 is a wasteful number, since it uses less digits than its factorization.

21789277665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1452618519.

The product of its digits is 17781120, while the sum is 60.

The spelling of 21789277665 in words is "twenty-one billion, seven hundred eighty-nine million, two hundred seventy-seven thousand, six hundred sixty-five".