217981422 has 16 divisors (see below), whose sum is σ = 484403280. Its totient is φ = 72660456.

The previous prime is 217981399. The next prime is 217981427. The reversal of 217981422 is 224189712.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (217981427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2018293 + ... + 2018400.

It is an arithmetic number, because the mean of its divisors is an integer number (30275205).

Almost surely, 2^217981422 is an apocalyptic number.

217981422 is an abundant number, since it is smaller than the sum of its proper divisors (266421858).

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

217981422 is a wasteful number, since it uses less digits than its factorization.

217981422 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4036704 (or 4036698 counting only the distinct ones).

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

The square root of 217981422 is about 14764.1939163640. The cubic root of 217981422 is about 601.8290685147.

It can be divided in two parts, 21798 and 1422, that added together give a triangular number (23220 = T₂₁₅).

The spelling of 217981422 in words is "two hundred seventeen million, nine hundred eighty-one thousand, four hundred twenty-two".