206972309 has 4 divisors (see below), whose sum is σ = 207251616. Its totient is φ = 206693004.

The previous prime is 206972303. The next prime is 206972317. The reversal of 206972309 is 903279602.

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 a cyclic number.

It is not a de Polignac number, because 206972309 - 2⁸ = 206972053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206972303) 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 3 ways as a sum of consecutive naturals, for example, 138539 + ... + 140024.

It is an arithmetic number, because the mean of its divisors is an integer number (51812904).

Almost surely, 2^206972309 is an apocalyptic number.

It is an amenable number.

206972309 is a deficient number, since it is larger than the sum of its proper divisors (279307).

206972309 is an equidigital number, since it uses as much as digits as its factorization.

206972309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279306.

The product of its (nonzero) digits is 40824, while the sum is 38.

The square root of 206972309 is about 14386.5322089793. The cubic root of 206972309 is about 591.5217910798.

The spelling of 206972309 in words is "two hundred six million, nine hundred seventy-two thousand, three hundred nine".