205420691520 has 1344 divisors, whose sum is σ = 845257900032. Its totient is φ = 47029248000.

The previous prime is 205420691503. The next prime is 205420691521. The reversal of 205420691520 is 25196024502.

205420691520 is a `hidden beast` number, since 2 + 0 + 5 + 42 + 0 + 6 + 91 + 520 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (205420691521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1617485697 + ... + 1617485823.

It is an arithmetic number, because the mean of its divisors is an integer number (628912128).

Almost surely, 2^205420691520 is an apocalyptic number.

205420691520 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 205420691520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (422628950016).

205420691520 is an abundant number, since it is smaller than the sum of its proper divisors (639837208512).

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

205420691520 is a wasteful number, since it uses less digits than its factorization.

205420691520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262 (or 240 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The spelling of 205420691520 in words is "two hundred five billion, four hundred twenty million, six hundred ninety-one thousand, five hundred twenty".