215173521423 has 48 divisors (see below), whose sum is σ = 366641267200. Its totient is φ = 119031726528.

The previous prime is 215173521377. The next prime is 215173521491. The reversal of 215173521423 is 324125371512.

215173521423 is a `hidden beast` number, since 2 + 15 + 173 + 52 + 1 + 423 = 666.

It is a Cunningham number, because it is equal to 463868²-1.

It is not a de Polignac number, because 215173521423 - 2¹⁷ = 215173390351 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215173521923) 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 47 ways as a sum of consecutive naturals, for example, 231936 + ... + 695802.

Almost surely, 2^215173521423 is an apocalyptic number.

215173521423 is a deficient number, since it is larger than the sum of its proper divisors (151467745777).

215173521423 is a wasteful number, since it uses less digits than its factorization.

215173521423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464116 (or 464113 counting only the distinct ones).

The product of its digits is 50400, while the sum is 36.

Adding to 215173521423 its reverse (324125371512), we get a palindrome (539298892935).

The spelling of 215173521423 in words is "two hundred fifteen billion, one hundred seventy-three million, five hundred twenty-one thousand, four hundred twenty-three".