65561081 has 4 divisors (see below), whose sum is σ = 66459252. Its totient is φ = 64662912.

The previous prime is 65561071. The next prime is 65561087. The reversal of 65561081 is 18016556.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 29800681 + 35760400 = 5459^2 + 5980^2 .

It is a cyclic number.

It is not a de Polignac number, because 65561081 - 2²² = 61366777 is a prime.

It is a super-2 number, since 2×65561081² = 8596510683777122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (65561087) 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, 448976 + ... + 449121.

It is an arithmetic number, because the mean of its divisors is an integer number (16614813).

Almost surely, 2^65561081 is an apocalyptic number.

It is an amenable number.

65561081 is a deficient number, since it is larger than the sum of its proper divisors (898171).

65561081 is an equidigital number, since it uses as much as digits as its factorization.

65561081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 898170.

The product of its (nonzero) digits is 7200, while the sum is 32.

The square root of 65561081 is about 8096.9797455595. The cubic root of 65561081 is about 403.2261618282.

The spelling of 65561081 in words is "sixty-five million, five hundred sixty-one thousand, eighty-one".