21070651617 has 6 divisors (see below), whose sum is σ = 30435385682. Its totient is φ = 14047101072.

The previous prime is 21070651577. The next prime is 21070651619. The reversal of 21070651617 is 71615607012.

It can be written as a sum of positive squares in only one way, i.e., 20556677376 + 513974241 = 143376^2 + 22671^2 .

It is not a de Polignac number, because 21070651617 - 2³¹ = 18923167969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21070651619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1170591748 + ... + 1170591765.

Almost surely, 2^21070651617 is an apocalyptic number.

It is an amenable number.

21070651617 is a deficient number, since it is larger than the sum of its proper divisors (9364734065).

21070651617 is a wasteful number, since it uses less digits than its factorization.

21070651617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2341183519 (or 2341183516 counting only the distinct ones).

The product of its (nonzero) digits is 17640, while the sum is 36.

The spelling of 21070651617 in words is "twenty-one billion, seventy million, six hundred fifty-one thousand, six hundred seventeen".