647222561 has 2 divisors, whose sum is σ = 647222562. Its totient is φ = 647222560.

The previous prime is 647222539. The next prime is 647222573. The reversal of 647222561 is 165222746.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 532732561 + 114490000 = 23081^2 + 10700^2 .

It is a cyclic number.

It is not a de Polignac number, because 647222561 - 2⁶ = 647222497 is a prime.

It is not a weakly prime, because it can be changed into another prime (647222531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323611280 + 323611281.

It is an arithmetic number, because the mean of its divisors is an integer number (323611281).

Almost surely, 2^647222561 is an apocalyptic number.

It is an amenable number.

647222561 is a deficient number, since it is larger than the sum of its proper divisors (1).

647222561 is an equidigital number, since it uses as much as digits as its factorization.

647222561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 35.

The square root of 647222561 is about 25440.5691956764. The cubic root of 647222561 is about 865.0035354640.

The spelling of 647222561 in words is "six hundred forty-seven million, two hundred twenty-two thousand, five hundred sixty-one".