206778013 has 16 divisors (see below), whose sum is σ = 231305536. Its totient is φ = 183617280.

The previous prime is 206778001. The next prime is 206778023. The reversal of 206778013 is 310877602.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206778013 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 206778013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206778023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34693 + ... + 40213.

It is an arithmetic number, because the mean of its divisors is an integer number (14456596).

Almost surely, 2^206778013 is an apocalyptic number.

It is an amenable number.

206778013 is a deficient number, since it is larger than the sum of its proper divisors (24527523).

206778013 is a wasteful number, since it uses less digits than its factorization.

206778013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5644.

The product of its (nonzero) digits is 14112, while the sum is 34.

The square root of 206778013 is about 14379.7779190083. Note that the first 3 decimals coincide. The cubic root of 206778013 is about 591.3366353924.

The spelling of 206778013 in words is "two hundred six million, seven hundred seventy-eight thousand, thirteen".