217728135 has 32 divisors (see below), whose sum is σ = 396084480. Its totient is φ = 113418144.

The previous prime is 217728131. The next prime is 217728151. The reversal of 217728135 is 531827712.

217728135 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 217728135 - 2² = 217728131 is a prime.

It is a super-3 number, since 3×217728135³ (a number of 26 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 217728135.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217728131) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12949 + ... + 24558.

It is an arithmetic number, because the mean of its divisors is an integer number (12377640).

Almost surely, 2^217728135 is an apocalyptic number.

217728135 is a deficient number, since it is larger than the sum of its proper divisors (178356345).

217728135 is a wasteful number, since it uses less digits than its factorization.

217728135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37564 (or 37558 counting only the distinct ones).

The product of its digits is 23520, while the sum is 36.

The square root of 217728135 is about 14755.6136775127. The cubic root of 217728135 is about 601.5958765335.

The spelling of 217728135 in words is "two hundred seventeen million, seven hundred twenty-eight thousand, one hundred thirty-five".