21000010005617 has 2 divisors, whose sum is σ = 21000010005618. Its totient is φ = 21000010005616.

The previous prime is 21000010005607. The next prime is 21000010005697. The reversal of 21000010005617 is 71650001000012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19510233527521 + 1489776478096 = 4417039^2 + 1220564^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21000010005617 is a prime.

It is a super-2 number, since 2×21000010005617² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21000010005592 and 21000010005601.

It is not a weakly prime, because it can be changed into another prime (21000010005607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500005002808 + 10500005002809.

It is an arithmetic number, because the mean of its divisors is an integer number (10500005002809).

Almost surely, 2^{21000010005617} is an apocalyptic number.

It is an amenable number.

21000010005617 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000010005617 is an equidigital number, since it uses as much as digits as its factorization.

21000010005617 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 420, while the sum is 23.

Adding to 21000010005617 its reverse (71650001000012), we get a palindrome (92650011005629).

The spelling of 21000010005617 in words is "twenty-one trillion, ten million, five thousand, six hundred seventeen".