217812942 has 64 divisors (see below), whose sum is σ = 514900800. Its totient is φ = 68250240.

The previous prime is 217812929. The next prime is 217812943. The reversal of 217812942 is 249218712.

It is a junction number, because it is equal to n+sod(n) for n = 217812897 and 217812906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217812943) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 264892 + ... + 265712.

It is an arithmetic number, because the mean of its divisors is an integer number (8045325).

Almost surely, 2^217812942 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 217812942, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (257450400).

217812942 is an abundant number, since it is smaller than the sum of its proper divisors (297087858).

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

217812942 is an equidigital number, since it uses as much as digits as its factorization.

217812942 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 883 (or 843 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 217812942 is about 14758.4871175876. The cubic root of 217812942 is about 601.6739753343.

The spelling of 217812942 in words is "two hundred seventeen million, eight hundred twelve thousand, nine hundred forty-two".