1820880 has 100 divisors (see below), whose sum is σ = 6346692. Its totient is φ = 483840.

The previous prime is 1820869. The next prime is 1820891. The reversal of 1820880 is 880281.

It is an interprime number because it is at equal distance from previous prime (1820869) and next prime (1820891).

It can be written as a sum of positive squares in 2 ways, for example, as 944784 + 876096 = 972^2 + 936^2 .

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 polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6340 + ... + 6620.

2^1820880 is an apocalyptic number.

1820880 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 1820880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3173346).

1820880 is an abundant number, since it is smaller than the sum of its proper divisors (4525812).

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

1820880 is a wasteful number, since it uses less digits than its factorization.

1820880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 306 (or 291 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 27.

The square root of 1820880 is about 1349.3998666074. The cubic root of 1820880 is about 122.1125897830.

The spelling of 1820880 in words is "one million, eight hundred twenty thousand, eight hundred eighty".