206696620321 has 27 divisors (see below), whose sum is σ = 215799041241. Its totient is φ = 197975280384.

The previous prime is 206696620307. The next prime is 206696620379. The reversal of 206696620321 is 123026696602.

The square root of 206696620321 is 454639.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 4703902225 + 201992718096 = 68585^2 + 449436^2 .

It is not a de Polignac number, because 206696620321 - 2⁵ = 206696620289 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (206696620381) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1896299215 + ... + 1896299323.

It is an arithmetic number, because the mean of its divisors is an integer number (7992557083).

Almost surely, 2^206696620321 is an apocalyptic number.

206696620321 is the 454639-th square number.

206696620321 is the 227320-th centered octagonal number.

It is an amenable number.

206696620321 is a deficient number, since it is larger than the sum of its proper divisors (9102420920).

206696620321 is an frugal number, since it uses more digits than its factorization.

206696620321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 498 (or 249 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 43.

The spelling of 206696620321 in words is "two hundred six billion, six hundred ninety-six million, six hundred twenty thousand, three hundred twenty-one".