660622561 has 2 divisors, whose sum is σ = 660622562. Its totient is φ = 660622560.

The previous prime is 660622549. The next prime is 660622621. The reversal of 660622561 is 165226066.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 400800400 + 259822161 = 20020^2 + 16119^2 .

It is a cyclic number.

It is not a de Polignac number, because 660622561 - 2¹⁹ = 660098273 is a prime.

It is not a weakly prime, because it can be changed into another prime (660622541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330311280 + 330311281.

It is an arithmetic number, because the mean of its divisors is an integer number (330311281).

Almost surely, 2^660622561 is an apocalyptic number.

It is an amenable number.

660622561 is a deficient number, since it is larger than the sum of its proper divisors (1).

660622561 is an equidigital number, since it uses as much as digits as its factorization.

660622561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 660622561 is about 25702.5788783927. The cubic root of 660622561 is about 870.9324397502.

The spelling of 660622561 in words is "six hundred sixty million, six hundred twenty-two thousand, five hundred sixty-one".