221031247 has 2 divisors, whose sum is σ = 221031248. Its totient is φ = 221031246.

The previous prime is 221031211. The next prime is 221031257. The reversal of 221031247 is 742130122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221031247 - 2⁷ = 221031119 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221031257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110515623 + 110515624.

It is an arithmetic number, because the mean of its divisors is an integer number (110515624).

Almost surely, 2^221031247 is an apocalyptic number.

221031247 is a deficient number, since it is larger than the sum of its proper divisors (1).

221031247 is an equidigital number, since it uses as much as digits as its factorization.

221031247 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 221031247 is about 14867.1196605126. The cubic root of 221031247 is about 604.6228526173.

Adding to 221031247 its reverse (742130122), we get a palindrome (963161369).

The spelling of 221031247 in words is "two hundred twenty-one million, thirty-one thousand, two hundred forty-seven".