2121297840 has 60 divisors (see below), whose sum is σ = 7124027664. Its totient is φ = 565679232.

The previous prime is 2121297833. The next prime is 2121297847. The reversal of 2121297840 is 487921212.

It is an interprime number because it is at equal distance from previous prime (2121297833) and next prime (2121297847).

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 2121297795 and 2121297804.

It is not an unprimeable number, because it can be changed into a prime (2121297847) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1472404 + ... + 1473843.

Almost surely, 2^2121297840 is an apocalyptic number.

2121297840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2121297840 is an abundant number, since it is smaller than the sum of its proper divisors (5002729824).

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

2121297840 is a wasteful number, since it uses less digits than its factorization.

2121297840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2946266 (or 2946257 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 2121297840 is about 46057.5492183420. The cubic root of 2121297840 is about 1284.8937498891.

The spelling of 2121297840 in words is "two billion, one hundred twenty-one million, two hundred ninety-seven thousand, eight hundred forty".