21286643017 has 8 divisors (see below), whose sum is σ = 22116832200. Its totient is φ = 20462865024.

The previous prime is 21286643009. The next prime is 21286643069. The reversal of 21286643017 is 71034668212.

It can be written as a sum of positive squares in 4 ways, for example, as 12258032656 + 9028610361 = 110716^2 + 95019^2 .

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 21286643017 - 2³ = 21286643009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21286641017) 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, 1596028 + ... + 1609309.

It is an arithmetic number, because the mean of its divisors is an integer number (2764604025).

Almost surely, 2^21286643017 is an apocalyptic number.

It is an amenable number.

21286643017 is a deficient number, since it is larger than the sum of its proper divisors (830189183).

21286643017 is a wasteful number, since it uses less digits than its factorization.

21286643017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3205595.

The product of its (nonzero) digits is 96768, while the sum is 40.

The spelling of 21286643017 in words is "twenty-one billion, two hundred eighty-six million, six hundred forty-three thousand, seventeen".