17664897881 has 2 divisors, whose sum is σ = 17664897882. Its totient is φ = 17664897880.

The previous prime is 17664897871. The next prime is 17664897907. The reversal of 17664897881 is 18879846671.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12891331600 + 4773566281 = 113540^2 + 69091^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-17664897881 is a prime.

It is a super-2 number, since 2×17664897881² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (17664897841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8832448940 + 8832448941.

It is an arithmetic number, because the mean of its divisors is an integer number (8832448941).

Almost surely, 2^17664897881 is an apocalyptic number.

It is an amenable number.

17664897881 is a deficient number, since it is larger than the sum of its proper divisors (1).

17664897881 is an equidigital number, since it uses as much as digits as its factorization.

17664897881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32514048, while the sum is 65.

The spelling of 17664897881 in words is "seventeen billion, six hundred sixty-four million, eight hundred ninety-seven thousand, eight hundred eighty-one".