206343781 has 16 divisors (see below), whose sum is σ = 256245760. Its totient is φ = 162149040.

The previous prime is 206343779. The next prime is 206343791. The reversal of 206343781 is 187343602.

It is a happy number.

It is not a de Polignac number, because 206343781 - 2¹ = 206343779 is a prime.

It is a super-2 number, since 2×206343781² = 85155511914751922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206343701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20901 + ... + 29146.

It is an arithmetic number, because the mean of its divisors is an integer number (16015360).

Almost surely, 2^206343781 is an apocalyptic number.

It is an amenable number.

206343781 is a deficient number, since it is larger than the sum of its proper divisors (49901979).

206343781 is a wasteful number, since it uses less digits than its factorization.

206343781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50104.

The product of its (nonzero) digits is 24192, while the sum is 34.

The square root of 206343781 is about 14364.6712806106. The cubic root of 206343781 is about 590.9224113985.

The spelling of 206343781 in words is "two hundred six million, three hundred forty-three thousand, seven hundred eighty-one".