221042491 has 2 divisors, whose sum is σ = 221042492. Its totient is φ = 221042490.

The previous prime is 221042461. The next prime is 221042501. The reversal of 221042491 is 194240122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221042491 - 2¹³ = 221034299 is a prime.

It is not a weakly prime, because it can be changed into another prime (221042441) 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, 110521245 + 110521246.

It is an arithmetic number, because the mean of its divisors is an integer number (110521246).

Almost surely, 2^221042491 is an apocalyptic number.

221042491 is a deficient number, since it is larger than the sum of its proper divisors (1).

221042491 is an equidigital number, since it uses as much as digits as its factorization.

221042491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 221042491 is about 14867.4978056161. The cubic root of 221042491 is about 604.6331049597.

The spelling of 221042491 in words is "two hundred twenty-one million, forty-two thousand, four hundred ninety-one".