221289491 has 2 divisors, whose sum is σ = 221289492. Its totient is φ = 221289490.

The previous prime is 221289479. The next prime is 221289503. The reversal of 221289491 is 194982122.

It is a balanced prime because it is at equal distance from previous prime (221289479) and next prime (221289503).

It is a cyclic number.

It is not a de Polignac number, because 221289491 - 2⁶ = 221289427 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221289421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110644745 + 110644746.

It is an arithmetic number, because the mean of its divisors is an integer number (110644746).

Almost surely, 2^221289491 is an apocalyptic number.

221289491 is a deficient number, since it is larger than the sum of its proper divisors (1).

221289491 is an equidigital number, since it uses as much as digits as its factorization.

221289491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20736, while the sum is 38.

The square root of 221289491 is about 14875.8021968565. The cubic root of 221289491 is about 604.8582332949.

The spelling of 221289491 in words is "two hundred twenty-one million, two hundred eighty-nine thousand, four hundred ninety-one".