205409389620 has 24 divisors (see below), whose sum is σ = 575146291104. Its totient is φ = 54775837216.

The previous prime is 205409389613. The next prime is 205409389643. The reversal of 205409389620 is 26983904502.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 205409389620.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1711744854 + ... + 1711744973.

It is an arithmetic number, because the mean of its divisors is an integer number (23964428796).

Almost surely, 2^205409389620 is an apocalyptic number.

205409389620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205409389620 is an abundant number, since it is smaller than the sum of its proper divisors (369736901484).

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

205409389620 is a wasteful number, since it uses less digits than its factorization.

205409389620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3423489839 (or 3423489837 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 48.

The spelling of 205409389620 in words is "two hundred five billion, four hundred nine million, three hundred eighty-nine thousand, six hundred twenty".