5671321781 has 2 divisors, whose sum is σ = 5671321782. Its totient is φ = 5671321780.

The previous prime is 5671321769. The next prime is 5671321783. The reversal of 5671321781 is 1871231765.

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., 4304540881 + 1366780900 = 65609^2 + 36970^2 .

It is a cyclic number.

It is not a de Polignac number, because 5671321781 - 2³⁰ = 4597579957 is a prime.

It is a super-2 number, since 2×5671321781² = 64327781487290023922, which contains 22 as substring.

Together with 5671321783, 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 (5671321783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2835660890 + 2835660891.

It is an arithmetic number, because the mean of its divisors is an integer number (2835660891).

Almost surely, 2^5671321781 is an apocalyptic number.

It is an amenable number.

5671321781 is a deficient number, since it is larger than the sum of its proper divisors (1).

5671321781 is an equidigital number, since it uses as much as digits as its factorization.

5671321781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 70560, while the sum is 41.

The square root of 5671321781 is about 75308.1787125409. The cubic root of 5671321781 is about 1783.3151387862.

The spelling of 5671321781 in words is "five billion, six hundred seventy-one million, three hundred twenty-one thousand, seven hundred eighty-one".