217530652638 has 64 divisors (see below), whose sum is σ = 473348619072. Its totient is φ = 66244300800.

The previous prime is 217530652627. The next prime is 217530652643. The reversal of 217530652638 is 836256035712.

It is a happy number.

It is a super-2 number, since 2×217530652638² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 35581870 + ... + 35587982.

It is an arithmetic number, because the mean of its divisors is an integer number (7396072173).

Almost surely, 2^217530652638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217530652638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (236674309536).

217530652638 is an abundant number, since it is smaller than the sum of its proper divisors (255817966434).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

217530652638 is a wasteful number, since it uses less digits than its factorization.

217530652638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10749.

The product of its (nonzero) digits is 1814400, while the sum is 48.

The spelling of 217530652638 in words is "two hundred seventeen billion, five hundred thirty million, six hundred fifty-two thousand, six hundred thirty-eight".