206018640 has 100 divisors (see below), whose sum is σ = 715555764. Its totient is φ = 54936576.

The previous prime is 206018621. The next prime is 206018647. The reversal of 206018640 is 46810602.

206018640 is a `hidden beast` number, since 2 + 0 + 6 + 0 + 18 + 640 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 114318864 + 91699776 = 10692^2 + 9576^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206018647) 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 19 ways as a sum of consecutive naturals, for example, 9417 + ... + 22376.

Almost surely, 2^206018640 is an apocalyptic number.

206018640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

206018640 is an abundant number, since it is smaller than the sum of its proper divisors (509537124).

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

206018640 is a wasteful number, since it uses less digits than its factorization.

206018640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31818 (or 31803 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 206018640 is about 14353.3494348880. The cubic root of 206018640 is about 590.6118712123.

It can be divided in two parts, 20601 and 8640, that added together give a square (29241 = 171²).

The spelling of 206018640 in words is "two hundred six million, eighteen thousand, six hundred forty".