221440981 has 2 divisors, whose sum is σ = 221440982. Its totient is φ = 221440980.

The previous prime is 221440979. The next prime is 221441053. The reversal of 221440981 is 189044122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 144720900 + 76720081 = 12030^2 + 8759^2 .

It is a cyclic number.

It is not a de Polignac number, because 221440981 - 2¹ = 221440979 is a prime.

It is a super-2 number, since 2×221440981² = 98072216132484722, which contains 22 as substring.

Together with 221440979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221440381) 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, 110720490 + 110720491.

It is an arithmetic number, because the mean of its divisors is an integer number (110720491).

Almost surely, 2^221440981 is an apocalyptic number.

It is an amenable number.

221440981 is a deficient number, since it is larger than the sum of its proper divisors (1).

221440981 is an equidigital number, since it uses as much as digits as its factorization.

221440981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 221440981 is about 14880.8931519583. The cubic root of 221440981 is about 604.9962260994.

The spelling of 221440981 in words is "two hundred twenty-one million, four hundred forty thousand, nine hundred eighty-one".