1780920 has 128 divisors (see below), whose sum is σ = 6350400. Its totient is φ = 442368.

The previous prime is 1780901. The next prime is 1780939. The reversal of 1780920 is 290871.

1780920 = T₈₉ + T₉₀ + ... + T₂₂₄.

It is an interprime number because it is at equal distance from previous prime (1780901) and next prime (1780939).

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 31 ways as a sum of consecutive naturals, for example, 18312 + ... + 18408.

2^1780920 is an apocalyptic number.

1780920 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 1780920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3175200).

1780920 is an abundant number, since it is smaller than the sum of its proper divisors (4569480).

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

1780920 is a wasteful number, since it uses less digits than its factorization.

1780920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134 (or 124 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 1780920 is about 1334.5111464503. The cubic root of 1780920 is about 121.2127033053.

The spelling of 1780920 in words is "one million, seven hundred eighty thousand, nine hundred twenty".