217031129955 has 96 divisors (see below), whose sum is σ = 403540300800. Its totient is φ = 107621395200.

The previous prime is 217031129951. The next prime is 217031129977. The reversal of 217031129955 is 559921130712.

It is a Cunningham number, because it is equal to 465866²-1.

It is not a de Polignac number, because 217031129955 - 2² = 217031129951 is a prime.

It is a super-2 number, since 2×217031129955² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 217031129955.

It is not an unprimeable number, because it can be changed into a prime (217031129951) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 53572680 + ... + 53576730.

It is an arithmetic number, because the mean of its divisors is an integer number (4203544800).

Almost surely, 2^217031129955 is an apocalyptic number.

217031129955 is a deficient number, since it is larger than the sum of its proper divisors (186509170845).

217031129955 is a wasteful number, since it uses less digits than its factorization.

217031129955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5521 (or 5518 counting only the distinct ones).

The product of its (nonzero) digits is 170100, while the sum is 45.

The spelling of 217031129955 in words is "two hundred seventeen billion, thirty-one million, one hundred twenty-nine thousand, nine hundred fifty-five".