2123735721 has 4 divisors (see below), whose sum is σ = 2831647632. Its totient is φ = 1415823812.

The previous prime is 2123735701. The next prime is 2123735771. The reversal of 2123735721 is 1275373212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2123735721 - 2⁵ = 2123735689 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2123735701) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 353955951 + ... + 353955956.

It is an arithmetic number, because the mean of its divisors is an integer number (707911908).

Almost surely, 2^2123735721 is an apocalyptic number.

It is an amenable number.

2123735721 is a deficient number, since it is larger than the sum of its proper divisors (707911911).

2123735721 is an equidigital number, since it uses as much as digits as its factorization.

2123735721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 707911910.

The product of its digits is 17640, while the sum is 33.

The square root of 2123735721 is about 46084.0072150849. The cubic root of 2123735721 is about 1285.3857786838.

The spelling of 2123735721 in words is "two billion, one hundred twenty-three million, seven hundred thirty-five thousand, seven hundred twenty-one".