221306947 has 2 divisors, whose sum is σ = 221306948. Its totient is φ = 221306946.

The previous prime is 221306941. The next prime is 221306993. The reversal of 221306947 is 749603122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221306947 - 2²³ = 212918339 is a prime.

It is not a weakly prime, because it can be changed into another prime (221306941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110653473 + 110653474.

It is an arithmetic number, because the mean of its divisors is an integer number (110653474).

Almost surely, 2^221306947 is an apocalyptic number.

221306947 is a deficient number, since it is larger than the sum of its proper divisors (1).

221306947 is an equidigital number, since it uses as much as digits as its factorization.

221306947 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 34.

The square root of 221306947 is about 14876.3889099472. The cubic root of 221306947 is about 604.8741372400.

The spelling of 221306947 in words is "two hundred twenty-one million, three hundred six thousand, nine hundred forty-seven".