2217978 has 48 divisors (see below), whose sum is σ = 5690880. Its totient is φ = 610848.

The previous prime is 2217967. The next prime is 2217991. The reversal of 2217978 is 8797122.

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 an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3351 + ... + 3957.

It is an arithmetic number, because the mean of its divisors is an integer number (118560).

2^2217978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2217978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2845440).

2217978 is an abundant number, since it is smaller than the sum of its proper divisors (3472902).

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

2217978 is a wasteful number, since it uses less digits than its factorization.

2217978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 651 (or 648 counting only the distinct ones).

The product of its digits is 14112, while the sum is 36.

The square root of 2217978 is about 1489.2877492278. The cubic root of 2217978 is about 130.4124572514.

The spelling of 2217978 in words is "two million, two hundred seventeen thousand, nine hundred seventy-eight".