21021006717 has 12 divisors (see below), whose sum is σ = 30490724160. Its totient is φ = 13955367048.

The previous prime is 21021006709. The next prime is 21021006767. The reversal of 21021006717 is 71760012012.

It is not a de Polignac number, because 21021006717 - 2³ = 21021006709 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021006767) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4884183 + ... + 4888484.

It is an arithmetic number, because the mean of its divisors is an integer number (2540893680).

Almost surely, 2^21021006717 is an apocalyptic number.

It is an amenable number.

21021006717 is a deficient number, since it is larger than the sum of its proper divisors (9469717443).

21021006717 is a wasteful number, since it uses less digits than its factorization.

21021006717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9772912 (or 9772909 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 27.

Adding to 21021006717 its reverse (71760012012), we get a palindrome (92781018729).

The spelling of 21021006717 in words is "twenty-one billion, twenty-one million, six thousand, seven hundred seventeen".