221002081 has 2 divisors, whose sum is σ = 221002082. Its totient is φ = 221002080.

The previous prime is 221002079. The next prime is 221002087. The reversal of 221002081 is 180200122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 220968225 + 33856 = 14865^2 + 184^2 .

It is a cyclic number.

It is not a de Polignac number, because 221002081 - 2¹ = 221002079 is a prime.

It is a super-2 number, since 2×221002081² = 97683839612661122, which contains 22 as substring.

Together with 221002079, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (221002087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110501040 + 110501041.

It is an arithmetic number, because the mean of its divisors is an integer number (110501041).

Almost surely, 2^221002081 is an apocalyptic number.

It is an amenable number.

221002081 is a deficient number, since it is larger than the sum of its proper divisors (1).

221002081 is an equidigital number, since it uses as much as digits as its factorization.

221002081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 221002081 is about 14866.1387387580. The cubic root of 221002081 is about 604.5962572738.

The spelling of 221002081 in words is "two hundred twenty-one million, two thousand, eighty-one".