217132681 has 4 divisors (see below), whose sum is σ = 218224000. Its totient is φ = 216041364.

The previous prime is 217132661. The next prime is 217132691. The reversal of 217132681 is 186231712.

217132681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217132681 is a prime.

It is a super-2 number, since 2×217132681² = 94293202316495522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (217132651) 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, 545361 + ... + 545758.

It is an arithmetic number, because the mean of its divisors is an integer number (54556000).

Almost surely, 2^217132681 is an apocalyptic number.

It is an amenable number.

217132681 is a deficient number, since it is larger than the sum of its proper divisors (1091319).

217132681 is a wasteful number, since it uses less digits than its factorization.

217132681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1091318.

The product of its digits is 4032, while the sum is 31.

The square root of 217132681 is about 14735.4226610573. The cubic root of 217132681 is about 601.0469507979.

The spelling of 217132681 in words is "two hundred seventeen million, one hundred thirty-two thousand, six hundred eighty-one".