221931902581 has 2 divisors, whose sum is σ = 221931902582. Its totient is φ = 221931902580.

The previous prime is 221931902537. The next prime is 221931902593. The reversal of 221931902581 is 185209139122.

221931902581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 201322716100 + 20609186481 = 448690^2 + 143559^2 .

It is a cyclic number.

It is not a de Polignac number, because 221931902581 - 2²⁷ = 221797684853 is a prime.

It is a super-2 number, since 2×221931902581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221931902081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110965951290 + 110965951291.

It is an arithmetic number, because the mean of its divisors is an integer number (110965951291).

Almost surely, 2^221931902581 is an apocalyptic number.

It is an amenable number.

221931902581 is a deficient number, since it is larger than the sum of its proper divisors (1).

221931902581 is an equidigital number, since it uses as much as digits as its factorization.

221931902581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 43.

The spelling of 221931902581 in words is "two hundred twenty-one billion, nine hundred thirty-one million, nine hundred two thousand, five hundred eighty-one".