217481389801 has 27 divisors (see below), whose sum is σ = 244095555951. Its totient is φ = 193672874304.

The previous prime is 217481389799. The next prime is 217481389843. The reversal of 217481389801 is 108983184712.

The square root of 217481389801 is 466349.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 13 ways, for example, as 129995581401 + 87485808400 = 360549^2 + 295780^2 .

It is not a de Polignac number, because 217481389801 - 2¹ = 217481389799 is a prime.

It is not an unprimeable number, because it can be changed into a prime (217481389871) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 175812955 + ... + 175814191.

Almost surely, 2^217481389801 is an apocalyptic number.

217481389801 is the 466349-th square number.

217481389801 is the 233175-th centered octagonal number.

It is an amenable number.

217481389801 is a deficient number, since it is larger than the sum of its proper divisors (26614166150).

217481389801 is an frugal number, since it uses more digits than its factorization.

217481389801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2558 (or 1279 counting only the distinct ones).

The product of its (nonzero) digits is 774144, while the sum is 52.

The spelling of 217481389801 in words is "two hundred seventeen billion, four hundred eighty-one million, three hundred eighty-nine thousand, eight hundred one".