2217780 has 90 divisors (see below), whose sum is σ = 7150374. Its totient is φ = 575424.

The previous prime is 2217779. The next prime is 2217799. The reversal of 2217780 is 877122.

2217780 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 1089936 + 1127844 = 1044^2 + 1062^2 .

It is a tau number, because it is divible by the number of its divisors (90).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 59922 + ... + 59958.

2^2217780 is an apocalyptic number.

2217780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2217780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3575187).

2217780 is an abundant number, since it is smaller than the sum of its proper divisors (4932594).

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

2217780 is a wasteful number, since it uses less digits than its factorization.

2217780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95 (or 47 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The square root of 2217780 is about 1489.2212730149. The cubic root of 2217780 is about 130.4085764743.

It can be divided in two parts, 221 and 7780, that added together give a triangular number (8001 = T₁₂₆).

The spelling of 2217780 in words is "two million, two hundred seventeen thousand, seven hundred eighty".