21497717611 has 2 divisors, whose sum is σ = 21497717612. Its totient is φ = 21497717610.

The previous prime is 21497717597. The next prime is 21497717617. The reversal of 21497717611 is 11671779412.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21497717611 - 2¹¹ = 21497715563 is a prime.

It is not a weakly prime, because it can be changed into another prime (21497717617) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10748858805 + 10748858806.

It is an arithmetic number, because the mean of its divisors is an integer number (10748858806).

Almost surely, 2^21497717611 is an apocalyptic number.

21497717611 is a deficient number, since it is larger than the sum of its proper divisors (1).

21497717611 is an equidigital number, since it uses as much as digits as its factorization.

21497717611 is an evil number, because the sum of its binary digits is even.

The product of its digits is 148176, while the sum is 46.

The spelling of 21497717611 in words is "twenty-one billion, four hundred ninety-seven million, seven hundred seventeen thousand, six hundred eleven".