2121071820 has 144 divisors (see below), whose sum is σ = 6925056768. Its totient is φ = 483665280.

The previous prime is 2121071791. The next prime is 2121071833. The reversal of 2121071820 is 281701212.

It is a super-2 number, since 2×2121071820² = 8997891331196224800, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2183935 + ... + 2184905.

It is an arithmetic number, because the mean of its divisors is an integer number (48090672).

Almost surely, 2^2121071820 is an apocalyptic number.

2121071820 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 2121071820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3462528384).

2121071820 is an abundant number, since it is smaller than the sum of its proper divisors (4803984948).

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

2121071820 is a wasteful number, since it uses less digits than its factorization.

2121071820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1740 (or 1731 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 2121071820 is about 46055.0954835619. The cubic root of 2121071820 is about 1284.8481139903.

The spelling of 2121071820 in words is "two billion, one hundred twenty-one million, seventy-one thousand, eight hundred twenty".