1641163261 has 2 divisors, whose sum is σ = 1641163262. Its totient is φ = 1641163260.

The previous prime is 1641163259. The next prime is 1641163267. The reversal of 1641163261 is 1623611461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1591531236 + 49632025 = 39894^2 + 7045^2 .

It is a cyclic number.

It is not a de Polignac number, because 1641163261 - 2¹ = 1641163259 is a prime.

Together with 1641163259, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1641163267) 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, 820581630 + 820581631.

It is an arithmetic number, because the mean of its divisors is an integer number (820581631).

Almost surely, 2^1641163261 is an apocalyptic number.

It is an amenable number.

1641163261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1641163261 is an equidigital number, since it uses as much as digits as its factorization.

1641163261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5184, while the sum is 31.

The square root of 1641163261 is about 40511.2732581932. The cubic root of 1641163261 is about 1179.5524638677.

The spelling of 1641163261 in words is "one billion, six hundred forty-one million, one hundred sixty-three thousand, two hundred sixty-one".