83131781 has 2 divisors, whose sum is σ = 83131782. Its totient is φ = 83131780.

The previous prime is 83131753. The next prime is 83131799. The reversal of 83131781 is 18713138.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80013025 + 3118756 = 8945^2 + 1766^2 .

It is a cyclic number.

It is not a de Polignac number, because 83131781 - 2¹⁸ = 82869637 is a prime.

It is a super-2 number, since 2×83131781² = 13821786024463922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (83131381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41565890 + 41565891.

It is an arithmetic number, because the mean of its divisors is an integer number (41565891).

Almost surely, 2^83131781 is an apocalyptic number.

It is an amenable number.

83131781 is a deficient number, since it is larger than the sum of its proper divisors (1).

83131781 is an equidigital number, since it uses as much as digits as its factorization.

83131781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 32.

The square root of 83131781 is about 9117.6631326234. The cubic root of 83131781 is about 436.4378037219.

The spelling of 83131781 in words is "eighty-three million, one hundred thirty-one thousand, seven hundred eighty-one".