1641241661 has 4 divisors (see below), whose sum is σ = 1668147324. Its totient is φ = 1614336000.

The previous prime is 1641241643. The next prime is 1641241663. The reversal of 1641241661 is 1661421461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1661421461 = 7 ⋅237345923.

It can be written as a sum of positive squares in 2 ways, for example, as 152053561 + 1489188100 = 12331^2 + 38590^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1641241661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1641241663) 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 in 3 ways as a sum of consecutive naturals, for example, 13452740 + ... + 13452861.

It is an arithmetic number, because the mean of its divisors is an integer number (417036831).

Almost surely, 2^1641241661 is an apocalyptic number.

It is an amenable number.

1641241661 is a deficient number, since it is larger than the sum of its proper divisors (26905663).

1641241661 is an equidigital number, since it uses as much as digits as its factorization.

1641241661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26905662.

The product of its digits is 6912, while the sum is 32.

The square root of 1641241661 is about 40512.2408785295. The cubic root of 1641241661 is about 1179.5712463664.

The spelling of 1641241661 in words is "one billion, six hundred forty-one million, two hundred forty-one thousand, six hundred sixty-one".