21670316881 has 2 divisors, whose sum is σ = 21670316882. Its totient is φ = 21670316880.

The previous prime is 21670316879. The next prime is 21670316897. The reversal of 21670316881 is 18861307612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13440924225 + 8229392656 = 115935^2 + 90716^2 .

It is a cyclic number.

It is not a de Polignac number, because 21670316881 - 2¹ = 21670316879 is a prime.

It is a super-2 number, since 2×21670316881² (a number of 21 digits) contains 22 as substring.

Together with 21670316879, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21670316821) 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 as a sum of consecutive naturals, namely, 10835158440 + 10835158441.

It is an arithmetic number, because the mean of its divisors is an integer number (10835158441).

Almost surely, 2^21670316881 is an apocalyptic number.

It is an amenable number.

21670316881 is a deficient number, since it is larger than the sum of its proper divisors (1).

21670316881 is an equidigital number, since it uses as much as digits as its factorization.

21670316881 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96768, while the sum is 43.

The spelling of 21670316881 in words is "twenty-one billion, six hundred seventy million, three hundred sixteen thousand, eight hundred eighty-one".