205054640490 has 128 divisors (see below), whose sum is σ = 565228707840. Its totient is φ = 46637337600.

The previous prime is 205054640431. The next prime is 205054640491. The reversal of 205054640490 is 94046450502.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (205054640491) 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, 57420405 + ... + 57423975.

It is an arithmetic number, because the mean of its divisors is an integer number (4415849280).

Almost surely, 2^205054640490 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205054640490, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (282614353920).

205054640490 is an abundant number, since it is smaller than the sum of its proper divisors (360174067350).

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

205054640490 is a wasteful number, since it uses less digits than its factorization.

205054640490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4868.

The product of its (nonzero) digits is 172800, while the sum is 39.

The spelling of 205054640490 in words is "two hundred five billion, fifty-four million, six hundred forty thousand, four hundred ninety".