206665016731 has 4 divisors (see below), whose sum is σ = 206748587752. Its totient is φ = 206581445712.

The previous prime is 206665016729. The next prime is 206665016749. The reversal of 206665016731 is 137610566602.

206665016731 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 137610566602 = 2 ⋅68805283301.

It is a cyclic number.

It is not a de Polignac number, because 206665016731 - 2¹ = 206665016729 is a prime.

It is a super-2 number, since 2×206665016731² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (206665010731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41781801 + ... + 41786746.

It is an arithmetic number, because the mean of its divisors is an integer number (51687146938).

Almost surely, 2^206665016731 is an apocalyptic number.

206665016731 is a deficient number, since it is larger than the sum of its proper divisors (83571021).

206665016731 is an equidigital number, since it uses as much as digits as its factorization.

206665016731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83571020.

The product of its (nonzero) digits is 272160, while the sum is 43.

The spelling of 206665016731 in words is "two hundred six billion, six hundred sixty-five million, sixteen thousand, seven hundred thirty-one".