206491780 has 72 divisors (see below), whose sum is σ = 483477120. Its totient is φ = 73457280.

The previous prime is 206491777. The next prime is 206491781. The reversal of 206491780 is 87194602.

It is not an unprimeable number, because it can be changed into a prime (206491781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1894366 + ... + 1894474.

It is an arithmetic number, because the mean of its divisors is an integer number (6714960).

Almost surely, 2^206491780 is an apocalyptic number.

206491780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 206491780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (241738560).

206491780 is an abundant number, since it is smaller than the sum of its proper divisors (276985340).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

206491780 is a wasteful number, since it uses less digits than its factorization.

206491780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 317 (or 206 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 37.

The square root of 206491780 is about 14369.8218499743. The cubic root of 206491780 is about 591.0636563066.

The spelling of 206491780 in words is "two hundred six million, four hundred ninety-one thousand, seven hundred eighty".