1205820 has 192 divisors, whose sum is σ = 4838400. Its totient is φ = 241920.

The previous prime is 1205819. The next prime is 1205843. The reversal of 1205820 is 285021.

Added to its reverse (285021) it gives a square (1490841 = 1221²).

It is a super-3 number, since 3×1205820³ = 5259793613332104000, which contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 1205793 and 1205802.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 41566 + ... + 41594.

It is an arithmetic number, because the mean of its divisors is an integer number (25200).

2^1205820 is an apocalyptic number.

1205820 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 1205820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2419200).

1205820 is an abundant number, since it is smaller than the sum of its proper divisors (3632580).

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

1205820 is a wasteful number, since it uses less digits than its factorization.

1205820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65 (or 57 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 1205820 is about 1098.0983562505. The cubic root of 1205820 is about 106.4373763953.

Adding to 1205820 its reverse (285021), we get a square (1490841 = 1221²).

It can be divided in two parts, 1205 and 820, that added together give a square (2025 = 45²).

The spelling of 1205820 in words is "one million, two hundred five thousand, eight hundred twenty".