1205821920 has 192 divisors, whose sum is σ = 3988776960. Its totient is φ = 305614848.

The previous prime is 1205821919. The next prime is 1205821961. The reversal of 1205821920 is 291285021.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

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, 2638332 + ... + 2638788.

It is an arithmetic number, because the mean of its divisors is an integer number (20774880).

Almost surely, 2^1205821920 is an apocalyptic number.

1205821920 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 1205821920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1994388480).

1205821920 is an abundant number, since it is smaller than the sum of its proper divisors (2782955040).

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

1205821920 is a wasteful number, since it uses less digits than its factorization.

1205821920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 737 (or 729 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 30.

The square root of 1205821920 is about 34724.9466522268. The cubic root of 1205821920 is about 1064.3743288784.

The spelling of 1205821920 in words is "one billion, two hundred five million, eight hundred twenty-one thousand, nine hundred twenty".