205215202101 has 48 divisors (see below), whose sum is σ = 348396534528. Its totient is φ = 106470806400.

The previous prime is 205215202079. The next prime is 205215202111. The reversal of 205215202101 is 101202512502.

It is not a de Polignac number, because 205215202101 - 2⁵ = 205215202069 is a prime.

It is a super-2 number, since 2×205215202101² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205215202111) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 763645 + ... + 996786.

It is an arithmetic number, because the mean of its divisors is an integer number (7258261136).

Almost surely, 2^205215202101 is an apocalyptic number.

205215202101 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

205215202101 is a deficient number, since it is larger than the sum of its proper divisors (143181332427).

205215202101 is a wasteful number, since it uses less digits than its factorization.

205215202101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1760522 (or 1760515 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 21.

Adding to 205215202101 its reverse (101202512502), we get a palindrome (306417714603).

The spelling of 205215202101 in words is "two hundred five billion, two hundred fifteen million, two hundred two thousand, one hundred one".