906685781 has 2 divisors, whose sum is σ = 906685782. Its totient is φ = 906685780.

The previous prime is 906685771. The next prime is 906685853. The reversal of 906685781 is 187586609.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 771172900 + 135512881 = 27770^2 + 11641^2 .

It is a cyclic number.

It is not a de Polignac number, because 906685781 - 2¹⁴ = 906669397 is a prime.

It is a super-2 number, since 2×906685781² = 1644158210935159922, 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 (906685721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 453342890 + 453342891.

It is an arithmetic number, because the mean of its divisors is an integer number (453342891).

Almost surely, 2^906685781 is an apocalyptic number.

It is an amenable number.

906685781 is a deficient number, since it is larger than the sum of its proper divisors (1).

906685781 is an equidigital number, since it uses as much as digits as its factorization.

906685781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 725760, while the sum is 50.

The square root of 906685781 is about 30111.2235055303. The cubic root of 906685781 is about 967.8742483578.

The spelling of 906685781 in words is "nine hundred six million, six hundred eighty-five thousand, seven hundred eighty-one".