204640666620 has 96 divisors (see below), whose sum is σ = 617856250368. Its totient is φ = 50308929792.

The previous prime is 204640666613. The next prime is 204640666631. The reversal of 204640666620 is 26666046402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 447177 + ... + 780543.

It is an arithmetic number, because the mean of its divisors is an integer number (6436002608).

Almost surely, 2^204640666620 is an apocalyptic number.

204640666620 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 204640666620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (308928125184).

204640666620 is an abundant number, since it is smaller than the sum of its proper divisors (413215583748).

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

204640666620 is a wasteful number, since it uses less digits than its factorization.

204640666620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334179 (or 334177 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 42.

The spelling of 204640666620 in words is "two hundred four billion, six hundred forty million, six hundred sixty-six thousand, six hundred twenty".