217256672641 has 8 divisors (see below), whose sum is σ = 231366170664. Its totient is φ = 203294918400.

The previous prime is 217256672621. The next prime is 217256672663. The reversal of 217256672641 is 146276652712.

It can be written as a sum of positive squares in 4 ways, for example, as 77439758400 + 139816914241 = 278280^2 + 373921^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 217256672641 - 2⁵ = 217256672609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217256672621) 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, 36932910 + ... + 36938791.

It is an arithmetic number, because the mean of its divisors is an integer number (28920771333).

Almost surely, 2^217256672641 is an apocalyptic number.

It is an amenable number.

217256672641 is a deficient number, since it is larger than the sum of its proper divisors (14109498023).

217256672641 is a wasteful number, since it uses less digits than its factorization.

217256672641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73871891.

The product of its digits is 1693440, while the sum is 49.

The spelling of 217256672641 in words is "two hundred seventeen billion, two hundred fifty-six million, six hundred seventy-two thousand, six hundred forty-one".