221012551 has 2 divisors, whose sum is σ = 221012552. Its totient is φ = 221012550.

The previous prime is 221012521. The next prime is 221012569. The reversal of 221012551 is 155210122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221012551 - 2⁹ = 221012039 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221012501) 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, 110506275 + 110506276.

It is an arithmetic number, because the mean of its divisors is an integer number (110506276).

Almost surely, 2^221012551 is an apocalyptic number.

221012551 is a deficient number, since it is larger than the sum of its proper divisors (1).

221012551 is an equidigital number, since it uses as much as digits as its factorization.

221012551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 221012551 is about 14866.4908771371. The cubic root of 221012551 is about 604.6058047297.

Adding to 221012551 its reverse (155210122), we get a palindrome (376222673).

The spelling of 221012551 in words is "two hundred twenty-one million, twelve thousand, five hundred fifty-one".