217870561431 has 8 divisors (see below), whose sum is σ = 322771202160. Its totient is φ = 145247040936.

The previous prime is 217870561351. The next prime is 217870561439. The reversal of 217870561431 is 134165078712.

217870561431 is a `hidden beast` number, since 2 + 1 + 7 + 87 + 0 + 561 + 4 + 3 + 1 = 666.

217870561431 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 217870561431 - 2⁷ = 217870561303 is a prime.

It is a super-2 number, since 2×217870561431² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217870561439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4034640000 + ... + 4034640053.

It is an arithmetic number, because the mean of its divisors is an integer number (40346400270).

Almost surely, 2^217870561431 is an apocalyptic number.

217870561431 is a deficient number, since it is larger than the sum of its proper divisors (104900640729).

217870561431 is an equidigital number, since it uses as much as digits as its factorization.

217870561431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8069280062 (or 8069280056 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 45.

The spelling of 217870561431 in words is "two hundred seventeen billion, eight hundred seventy million, five hundred sixty-one thousand, four hundred thirty-one".