206781869 has 4 divisors (see below), whose sum is σ = 236322144. Its totient is φ = 177241596.

The previous prime is 206781859. The next prime is 206781871. The reversal of 206781869 is 968187602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 206781869 - 2⁴ = 206781853 is a prime.

It is a super-2 number, since 2×206781869² = 85517482694266322, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206781859) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14770127 + ... + 14770140.

It is an arithmetic number, because the mean of its divisors is an integer number (59080536).

Almost surely, 2^206781869 is an apocalyptic number.

It is an amenable number.

206781869 is a deficient number, since it is larger than the sum of its proper divisors (29540275).

206781869 is an equidigital number, since it uses as much as digits as its factorization.

206781869 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29540274.

The product of its (nonzero) digits is 290304, while the sum is 47.

The square root of 206781869 is about 14379.9119955582. The cubic root of 206781869 is about 591.3403111215.

The spelling of 206781869 in words is "two hundred six million, seven hundred eighty-one thousand, eight hundred sixty-nine".