5631781 has 2 divisors, whose sum is σ = 5631782. Its totient is φ = 5631780.

The previous prime is 5631767. The next prime is 5631793. The reversal of 5631781 is 1871365.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5134756 + 497025 = 2266^2 + 705^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-5631781 is a prime.

It is a super-2 number, since 2×5631781² = 63433914463922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (5631701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2815890 + 2815891.

It is an arithmetic number, because the mean of its divisors is an integer number (2815891).

Almost surely, 2^5631781 is an apocalyptic number.

It is an amenable number.

5631781 is a deficient number, since it is larger than the sum of its proper divisors (1).

5631781 is an equidigital number, since it uses as much as digits as its factorization.

5631781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5040, while the sum is 31.

The square root of 5631781 is about 2373.1373748690. The cubic root of 5631781 is about 177.9161010999.

The spelling of 5631781 in words is "five million, six hundred thirty-one thousand, seven hundred eighty-one".