205021557240 has 64 divisors (see below), whose sum is σ = 620812978560. Its totient is φ = 54161454720.

The previous prime is 205021557163. The next prime is 205021557341. The reversal of 205021557240 is 42755120502.

It is a super-2 number, since 2×205021557240² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7970866 + ... + 7996545.

It is an arithmetic number, because the mean of its divisors is an integer number (9700202790).

Almost surely, 2^205021557240 is an apocalyptic number.

205021557240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205021557240 is an abundant number, since it is smaller than the sum of its proper divisors (415791421320).

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

205021557240 is a wasteful number, since it uses less digits than its factorization.

205021557240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15967532 (or 15967528 counting only the distinct ones).

The product of its (nonzero) digits is 28000, while the sum is 33.

Adding to 205021557240 its reverse (42755120502), we get a palindrome (247776677742).

The spelling of 205021557240 in words is "two hundred five billion, twenty-one million, five hundred fifty-seven thousand, two hundred forty".