205211021355 has 36 divisors (see below), whose sum is σ = 361087638912. Its totient is φ = 107812251360.

The previous prime is 205211021347. The next prime is 205211021441. The reversal of 205211021355 is 553120112502.

205211021355 is a `hidden beast` number, since 2 + 0 + 521 + 1 + 0 + 2 + 135 + 5 = 666.

It is not a de Polignac number, because 205211021355 - 2³ = 205211021347 is a prime.

It is a super-2 number, since 2×205211021355² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 305931 + ... + 709940.

It is an arithmetic number, because the mean of its divisors is an integer number (10030212192).

Almost surely, 2^205211021355 is an apocalyptic number.

205211021355 is a deficient number, since it is larger than the sum of its proper divisors (155876617557).

205211021355 is a wasteful number, since it uses less digits than its factorization.

205211021355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1016016 (or 1015946 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

Adding to 205211021355 its reverse (553120112502), we get a palindrome (758331133857).

The spelling of 205211021355 in words is "two hundred five billion, two hundred eleven million, twenty-one thousand, three hundred fifty-five".