1778220 has 96 divisors (see below), whose sum is σ = 5745600. Its totient is φ = 456192.

The previous prime is 1778219. The next prime is 1778221. The reversal of 1778220 is 228771.

It is an interprime number because it is at equal distance from previous prime (1778219) and next prime (1778221).

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

It is not an unprimeable number, because it can be changed into a prime (1778221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19936 + ... + 20024.

It is an arithmetic number, because the mean of its divisors is an integer number (59850).

2^1778220 is an apocalyptic number.

1778220 is a gapful number since it is divisible by the number (10) 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 1778220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2872800).

1778220 is an abundant number, since it is smaller than the sum of its proper divisors (3967380).

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

1778220 is a wasteful number, since it uses less digits than its factorization.

1778220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144 (or 136 counting only the distinct ones).

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

The square root of 1778220 is about 1333.4991563552. The cubic root of 1778220 is about 121.1514166616.

The spelling of 1778220 in words is "one million, seven hundred seventy-eight thousand, two hundred twenty".