390784561 has 2 divisors, whose sum is σ = 390784562. Its totient is φ = 390784560.

The previous prime is 390784547. The next prime is 390784567. The reversal of 390784561 is 165487093.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212722225 + 178062336 = 14585^2 + 13344^2 .

It is a cyclic number.

It is not a de Polignac number, because 390784561 - 2¹³ = 390776369 is a prime.

It is not a weakly prime, because it can be changed into another prime (390784567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195392280 + 195392281.

It is an arithmetic number, because the mean of its divisors is an integer number (195392281).

Almost surely, 2^390784561 is an apocalyptic number.

It is an amenable number.

390784561 is a deficient number, since it is larger than the sum of its proper divisors (1).

390784561 is an equidigital number, since it uses as much as digits as its factorization.

390784561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 181440, while the sum is 43.

The square root of 390784561 is about 19768.2715734077. The cubic root of 390784561 is about 731.1039536322.

The spelling of 390784561 in words is "three hundred ninety million, seven hundred eighty-four thousand, five hundred sixty-one".