217897955 has 8 divisors (see below), whose sum is σ = 285248304. Its totient is φ = 158471200.

The previous prime is 217897943. The next prime is 217897963. The reversal of 217897955 is 559798712.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 217897955 - 2¹² = 217893859 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 217897897 and 217897906.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1980836 + ... + 1980945.

It is an arithmetic number, because the mean of its divisors is an integer number (35656038).

Almost surely, 2^217897955 is an apocalyptic number.

217897955 is a deficient number, since it is larger than the sum of its proper divisors (67350349).

217897955 is a wasteful number, since it uses less digits than its factorization.

217897955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3961797.

The product of its digits is 1587600, while the sum is 53.

The square root of 217897955 is about 14761.3669759951. The cubic root of 217897955 is about 601.7522434971.

The spelling of 217897955 in words is "two hundred seventeen million, eight hundred ninety-seven thousand, nine hundred fifty-five".