206478990 has 128 divisors (see below), whose sum is σ = 574801920. Its totient is φ = 52700544.

The previous prime is 206478977. The next prime is 206478997. The reversal of 206478990 is 99874602.

It is a happy number.

It is a super-2 number, since 2×206478990² = 85267146622840200, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206478997) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 672417 + ... + 672723.

It is an arithmetic number, because the mean of its divisors is an integer number (4490640).

Almost surely, 2^206478990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 206478990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (287400960).

206478990 is an abundant number, since it is smaller than the sum of its proper divisors (368322930).

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

206478990 is a wasteful number, since it uses less digits than its factorization.

206478990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423 (or 417 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The square root of 206478990 is about 14369.3768132094. The cubic root of 206478990 is about 591.0514526566.

The spelling of 206478990 in words is "two hundred six million, four hundred seventy-eight thousand, nine hundred ninety".