1641165903521 has 2 divisors, whose sum is σ = 1641165903522. Its totient is φ = 1641165903520.

The previous prime is 1641165903439. The next prime is 1641165903613. The reversal of 1641165903521 is 1253095611461.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1108756350625 + 532409552896 = 1052975^2 + 729664^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1641165903521 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1641165903721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 820582951760 + 820582951761.

It is an arithmetic number, because the mean of its divisors is an integer number (820582951761).

Almost surely, 2^{1641165903521} is an apocalyptic number.

It is an amenable number.

1641165903521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1641165903521 is an equidigital number, since it uses as much as digits as its factorization.

1641165903521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 194400, while the sum is 44.

The spelling of 1641165903521 in words is "one trillion, six hundred forty-one billion, one hundred sixty-five million, nine hundred three thousand, five hundred twenty-one".