2121135720 has 64 divisors (see below), whose sum is σ = 6941903040. Its totient is φ = 514214400.

The previous prime is 2121135683. The next prime is 2121135767. The reversal of 2121135720 is 275311212.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 802141 + ... + 804780.

It is an arithmetic number, because the mean of its divisors is an integer number (108467235).

Almost surely, 2^2121135720 is an apocalyptic number.

2121135720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2121135720 is an abundant number, since it is smaller than the sum of its proper divisors (4820767320).

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

2121135720 is a wasteful number, since it uses less digits than its factorization.

2121135720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1606946 (or 1606942 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 24.

The square root of 2121135720 is about 46055.7892126495. The cubic root of 2121135720 is about 1284.8610164247.

Adding to 2121135720 its reverse (275311212), we get a palindrome (2396446932).

The spelling of 2121135720 in words is "two billion, one hundred twenty-one million, one hundred thirty-five thousand, seven hundred twenty".