221551441 has 2 divisors, whose sum is σ = 221551442. Its totient is φ = 221551440.

The previous prime is 221551439. The next prime is 221551459. The reversal of 221551441 is 144155122.

221551441 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 164865600 + 56685841 = 12840^2 + 7529^2 .

It is a cyclic number.

It is not a de Polignac number, because 221551441 - 2¹ = 221551439 is a prime.

Together with 221551439, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (221551411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110775720 + 110775721.

It is an arithmetic number, because the mean of its divisors is an integer number (110775721).

Almost surely, 2^221551441 is an apocalyptic number.

It is an amenable number.

221551441 is a deficient number, since it is larger than the sum of its proper divisors (1).

221551441 is an equidigital number, since it uses as much as digits as its factorization.

221551441 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1600, while the sum is 25.

The square root of 221551441 is about 14884.6041600037. The cubic root of 221551441 is about 605.0968048543.

The spelling of 221551441 in words is "two hundred twenty-one million, five hundred fifty-one thousand, four hundred forty-one".