2121151780 has 72 divisors (see below), whose sum is σ = 4976790840. Its totient is φ = 758630400.

The previous prime is 2121151777. The next prime is 2121151801. The reversal of 2121151780 is 871511212.

It can be written as a sum of positive squares in 4 ways, for example, as 11035684 + 2110116096 = 3322^2 + 45936^2 .

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 23 ways as a sum of consecutive naturals, for example, 140436 + ... + 154804.

It is an arithmetic number, because the mean of its divisors is an integer number (69122095).

Almost surely, 2^2121151780 is an apocalyptic number.

2121151780 is a gapful number since it is divisible by the number (20) 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 2121151780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2488395420).

2121151780 is an abundant number, since it is smaller than the sum of its proper divisors (2855639060).

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

2121151780 is a wasteful number, since it uses less digits than its factorization.

2121151780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14461 (or 14448 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 28.

The square root of 2121151780 is about 46055.9635660790. The cubic root of 2121151780 is about 1284.8642591555.

Adding to 2121151780 its reverse (871511212), we get a palindrome (2992662992).

The spelling of 2121151780 in words is "two billion, one hundred twenty-one million, one hundred fifty-one thousand, seven hundred eighty".