221940647 has 2 divisors, whose sum is σ = 221940648. Its totient is φ = 221940646.

The previous prime is 221940619. The next prime is 221940707. The reversal of 221940647 is 746049122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221940647 - 2⁶ = 221940583 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221942647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110970323 + 110970324.

It is an arithmetic number, because the mean of its divisors is an integer number (110970324).

Almost surely, 2^221940647 is an apocalyptic number.

221940647 is a deficient number, since it is larger than the sum of its proper divisors (1).

221940647 is an equidigital number, since it uses as much as digits as its factorization.

221940647 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 221940647 is about 14897.6725363394. The cubic root of 221940647 is about 605.4509280816.

Adding to 221940647 its reverse (746049122), we get a palindrome (967989769).

The spelling of 221940647 in words is "two hundred twenty-one million, nine hundred forty thousand, six hundred forty-seven".