205121651115 has 8 divisors (see below), whose sum is σ = 328194641808. Its totient is φ = 109398213920.

The previous prime is 205121651113. The next prime is 205121651179. The reversal of 205121651115 is 511156121502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 205121651115 - 2¹ = 205121651113 is a prime.

It is a super-2 number, since 2×205121651115² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (205121651113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6837388356 + ... + 6837388385.

It is an arithmetic number, because the mean of its divisors is an integer number (41024330226).

Almost surely, 2^205121651115 is an apocalyptic number.

205121651115 is a deficient number, since it is larger than the sum of its proper divisors (123072990693).

205121651115 is a wasteful number, since it uses less digits than its factorization.

205121651115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13674776749.

The product of its (nonzero) digits is 3000, while the sum is 30.

Adding to 205121651115 its reverse (511156121502), we get a palindrome (716277772617).

The spelling of 205121651115 in words is "two hundred five billion, one hundred twenty-one million, six hundred fifty-one thousand, one hundred fifteen".