2121200720 has 20 divisors (see below), whose sum is σ = 4931791860. Its totient is φ = 848480256.

The previous prime is 2121200693. The next prime is 2121200773. The reversal of 2121200720 is 270021212.

It can be written as a sum of positive squares in 2 ways, for example, as 675376144 + 1445824576 = 25988^2 + 38024^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-4 number, since 4×2121200720⁴ (a number of 38 digits) contains 4444 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13257425 + ... + 13257584.

It is an arithmetic number, because the mean of its divisors is an integer number (246589593).

Almost surely, 2^2121200720 is an apocalyptic number.

2121200720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2121200720 is an abundant number, since it is smaller than the sum of its proper divisors (2810591140).

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

2121200720 is a wasteful number, since it uses less digits than its factorization.

2121200720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26515022 (or 26515016 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 2121200720 is about 46056.4948731447. The cubic root of 2121200720 is about 1284.8741407009.

Adding to 2121200720 its reverse (270021212), we get a palindrome (2391221932).

The spelling of 2121200720 in words is "two billion, one hundred twenty-one million, two hundred thousand, seven hundred twenty".