206172137 has 4 divisors (see below), whose sum is σ = 209666640. Its totient is φ = 202677636.

The previous prime is 206172133. The next prime is 206172139. The reversal of 206172137 is 731271602.

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 206172137 - 2² = 206172133 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (206172133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1747163 + ... + 1747280.

It is an arithmetic number, because the mean of its divisors is an integer number (52416660).

Almost surely, 2^206172137 is an apocalyptic number.

It is an amenable number.

206172137 is a deficient number, since it is larger than the sum of its proper divisors (3494503).

206172137 is an equidigital number, since it uses as much as digits as its factorization.

206172137 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3494502.

The product of its (nonzero) digits is 3528, while the sum is 29.

The square root of 206172137 is about 14358.6955187440. The cubic root of 206172137 is about 590.7585159441.

The spelling of 206172137 in words is "two hundred six million, one hundred seventy-two thousand, one hundred thirty-seven".