221281493 has 2 divisors, whose sum is σ = 221281494. Its totient is φ = 221281492.

The previous prime is 221281453. The next prime is 221281507. The reversal of 221281493 is 394182122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 148401124 + 72880369 = 12182^2 + 8537^2 .

It is a cyclic number.

It is not a de Polignac number, because 221281493 - 2¹⁸ = 221019349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221281453) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110640746 + 110640747.

It is an arithmetic number, because the mean of its divisors is an integer number (110640747).

Almost surely, 2^221281493 is an apocalyptic number.

It is an amenable number.

221281493 is a deficient number, since it is larger than the sum of its proper divisors (1).

221281493 is an equidigital number, since it uses as much as digits as its factorization.

221281493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 32.

The square root of 221281493 is about 14875.5333685888. The cubic root of 221281493 is about 604.8509461370.

The spelling of 221281493 in words is "two hundred twenty-one million, two hundred eighty-one thousand, four hundred ninety-three".