1983664561 has 2 divisors, whose sum is σ = 1983664562. Its totient is φ = 1983664560.

The previous prime is 1983664517. The next prime is 1983664603. The reversal of 1983664561 is 1654663891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1790982400 + 192682161 = 42320^2 + 13881^2 .

It is a cyclic number.

It is not a de Polignac number, because 1983664561 - 2¹³ = 1983656369 is a prime.

It is not a weakly prime, because it can be changed into another prime (1983664861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 991832280 + 991832281.

It is an arithmetic number, because the mean of its divisors is an integer number (991832281).

Almost surely, 2^1983664561 is an apocalyptic number.

It is an amenable number.

1983664561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1983664561 is an equidigital number, since it uses as much as digits as its factorization.

1983664561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 933120, while the sum is 49.

The square root of 1983664561 is about 44538.3493295385. The cubic root of 1983664561 is about 1256.4814409985.

The spelling of 1983664561 in words is "one billion, nine hundred eighty-three million, six hundred sixty-four thousand, five hundred sixty-one".