21670505609 has 2 divisors, whose sum is σ = 21670505610. Its totient is φ = 21670505608.

The previous prime is 21670505599. The next prime is 21670505653. The reversal of 21670505609 is 90650507612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19391398009 + 2279107600 = 139253^2 + 47740^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21670505609 is a prime.

It is a super-2 number, since 2×21670505609² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21670505209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10835252804 + 10835252805.

It is an arithmetic number, because the mean of its divisors is an integer number (10835252805).

Almost surely, 2^21670505609 is an apocalyptic number.

It is an amenable number.

21670505609 is a deficient number, since it is larger than the sum of its proper divisors (1).

21670505609 is an equidigital number, since it uses as much as digits as its factorization.

21670505609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 113400, while the sum is 41.

The spelling of 21670505609 in words is "twenty-one billion, six hundred seventy million, five hundred five thousand, six hundred nine".