41665781 has 4 divisors (see below), whose sum is σ = 41678700. Its totient is φ = 41652864.

The previous prime is 41665777. The next prime is 41665783. The reversal of 41665781 is 18756614.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18756614 = 2 ⋅9378307.

It can be written as a sum of positive squares in 2 ways, for example, as 28408900 + 13256881 = 5330^2 + 3641^2 .

It is a cyclic number.

It is not a de Polignac number, because 41665781 - 2² = 41665777 is a prime.

It is a super-2 number, since 2×41665781² = 3472074612679922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (41665783) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2885 + ... + 9573.

It is an arithmetic number, because the mean of its divisors is an integer number (10419675).

Almost surely, 2^41665781 is an apocalyptic number.

It is an amenable number.

41665781 is a deficient number, since it is larger than the sum of its proper divisors (12919).

41665781 is an equidigital number, since it uses as much as digits as its factorization.

41665781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12918.

The product of its digits is 40320, while the sum is 38.

The square root of 41665781 is about 6454.9036398695. The cubic root of 41665781 is about 346.6781808100.

The spelling of 41665781 in words is "forty-one million, six hundred sixty-five thousand, seven hundred eighty-one".