21083408956081 has 2 divisors, whose sum is σ = 21083408956082. Its totient is φ = 21083408956080.

The previous prime is 21083408956067. The next prime is 21083408956117. The reversal of 21083408956081 is 18065980438012.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19747500641856 + 1335908314225 = 4443816^2 + 1155815^2 .

It is a cyclic number.

It is not a de Polignac number, because 21083408956081 - 2⁷ = 21083408955953 is a prime.

It is a super-2 number, since 2×21083408956081² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21083408954081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10541704478040 + 10541704478041.

It is an arithmetic number, because the mean of its divisors is an integer number (10541704478041).

Almost surely, 2^{21083408956081} is an apocalyptic number.

It is an amenable number.

21083408956081 is a deficient number, since it is larger than the sum of its proper divisors (1).

21083408956081 is an equidigital number, since it uses as much as digits as its factorization.

21083408956081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3317760, while the sum is 55.

The spelling of 21083408956081 in words is "twenty-one trillion, eighty-three billion, four hundred eight million, nine hundred fifty-six thousand, eighty-one".