215121551171 has 4 divisors (see below), whose sum is σ = 215122479312. Its totient is φ = 215120623032.

The previous prime is 215121551143. The next prime is 215121551179. The reversal of 215121551171 is 171155121512.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 215121551171 - 2⁶ = 215121551107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215121551179) 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, 208826 + ... + 688368.

It is an arithmetic number, because the mean of its divisors is an integer number (53780619828).

Almost surely, 2^215121551171 is an apocalyptic number.

215121551171 is a deficient number, since it is larger than the sum of its proper divisors (928141).

215121551171 is an equidigital number, since it uses as much as digits as its factorization.

215121551171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 928140.

The product of its digits is 3500, while the sum is 32.

Adding to 215121551171 its reverse (171155121512), we get a palindrome (386276672683).

The spelling of 215121551171 in words is "two hundred fifteen billion, one hundred twenty-one million, five hundred fifty-one thousand, one hundred seventy-one".