1664561963 has 2 divisors, whose sum is σ = 1664561964. Its totient is φ = 1664561962.

The previous prime is 1664561947. The next prime is 1664562023. The reversal of 1664561963 is 3691654661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1664561963 - 2⁴ = 1664561947 is a prime.

It is not a weakly prime, because it can be changed into another prime (1664561663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832280981 + 832280982.

It is an arithmetic number, because the mean of its divisors is an integer number (832280982).

Almost surely, 2^1664561963 is an apocalyptic number.

1664561963 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664561963 is an equidigital number, since it uses as much as digits as its factorization.

1664561963 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 699840, while the sum is 47.

The square root of 1664561963 is about 40799.0436530074. The cubic root of 1664561963 is about 1185.1318108406.

The spelling of 1664561963 in words is "one billion, six hundred sixty-four million, five hundred sixty-one thousand, nine hundred sixty-three".