20121172315177 has 4 divisors (see below), whose sum is σ = 21304770686676. Its totient is φ = 18937573943680.

The previous prime is 20121172315157. The next prime is 20121172315213. The reversal of 20121172315177 is 77151327112102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17211637013481 + 2909535301696 = 4148691^2 + 1705736^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121172315177 - 2¹¹ = 20121172313129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20121172315157) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 591799185724 + ... + 591799185757.

It is an arithmetic number, because the mean of its divisors is an integer number (5326192671669).

Almost surely, 2^{20121172315177} is an apocalyptic number.

It is an amenable number.

20121172315177 is a deficient number, since it is larger than the sum of its proper divisors (1183598371499).

20121172315177 is a wasteful number, since it uses less digits than its factorization.

20121172315177 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1183598371498.

The product of its (nonzero) digits is 41160, while the sum is 40.

Adding to 20121172315177 its reverse (77151327112102), we get a palindrome (97272499427279).

The spelling of 20121172315177 in words is "twenty trillion, one hundred twenty-one billion, one hundred seventy-two million, three hundred fifteen thousand, one hundred seventy-seven".