206405997 has 16 divisors (see below), whose sum is σ = 317412480. Its totient is φ = 116862912.

The previous prime is 206405989. The next prime is 206406007. The reversal of 206405997 is 799504602.

It is not a de Polignac number, because 206405997 - 2³ = 206405989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206405917) 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 15 ways as a sum of consecutive naturals, for example, 42798 + ... + 47375.

It is an arithmetic number, because the mean of its divisors is an integer number (19838280).

Almost surely, 2^206405997 is an apocalyptic number.

It is an amenable number.

206405997 is a deficient number, since it is larger than the sum of its proper divisors (111006483).

206405997 is a wasteful number, since it uses less digits than its factorization.

206405997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90292.

The product of its (nonzero) digits is 136080, while the sum is 42.

The square root of 206405997 is about 14366.8367081971. The cubic root of 206405997 is about 590.9817963306.

The spelling of 206405997 in words is "two hundred six million, four hundred five thousand, nine hundred ninety-seven".