1205120820 has 96 divisors (see below), whose sum is σ = 3584020608. Its totient is φ = 301514752.

The previous prime is 1205120797. The next prime is 1205120827. The reversal of 1205120820 is 280215021.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205120827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 358387 + ... + 361733.

It is an arithmetic number, because the mean of its divisors is an integer number (37333548).

Almost surely, 2^1205120820 is an apocalyptic number.

1205120820 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 1205120820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1792010304).

1205120820 is an abundant number, since it is smaller than the sum of its proper divisors (2378899788).

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

1205120820 is a wasteful number, since it uses less digits than its factorization.

1205120820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3729 (or 3727 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 1205120820 is about 34714.8501365050. The cubic root of 1205120820 is about 1064.1680028022.

Adding to 1205120820 its reverse (280215021), we get a palindrome (1485335841).

The spelling of 1205120820 in words is "one billion, two hundred five million, one hundred twenty thousand, eight hundred twenty".