206945581 has 2 divisors, whose sum is σ = 206945582. Its totient is φ = 206945580.

The previous prime is 206945569. The next prime is 206945591. The reversal of 206945581 is 185549602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 201498025 + 5447556 = 14195^2 + 2334^2 .

It is a cyclic number.

It is not a de Polignac number, because 206945581 - 2²¹ = 204848429 is a prime.

It is a super-2 number, since 2×206945581² = 85652946990855122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206945521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103472790 + 103472791.

It is an arithmetic number, because the mean of its divisors is an integer number (103472791).

Almost surely, 2^206945581 is an apocalyptic number.

It is an amenable number.

206945581 is a deficient number, since it is larger than the sum of its proper divisors (1).

206945581 is an equidigital number, since it uses as much as digits as its factorization.

206945581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 86400, while the sum is 40.

The square root of 206945581 is about 14385.6032546432. The cubic root of 206945581 is about 591.4963273272.

The spelling of 206945581 in words is "two hundred six million, nine hundred forty-five thousand, five hundred eighty-one".