5661281 has 2 divisors, whose sum is σ = 5661282. Its totient is φ = 5661280.

The previous prime is 5661277. The next prime is 5661283. The reversal of 5661281 is 1821665.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4661281 + 1000000 = 2159^2 + 1000^2 .

It is a cyclic number.

It is not a de Polignac number, because 5661281 - 2² = 5661277 is a prime.

It is a super-3 number, since 3×5661281³ (a number of 21 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

Together with 5661283, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5661283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2830640 + 2830641.

It is an arithmetic number, because the mean of its divisors is an integer number (2830641).

Almost surely, 2^5661281 is an apocalyptic number.

It is an amenable number.

5661281 is a deficient number, since it is larger than the sum of its proper divisors (1).

5661281 is an equidigital number, since it uses as much as digits as its factorization.

5661281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 29.

The square root of 5661281 is about 2379.3446576736. The cubic root of 5661281 is about 178.2262094775.

The spelling of 5661281 in words is "five million, six hundred sixty-one thousand, two hundred eighty-one".