2125635721 has 4 divisors (see below), whose sum is σ = 2318875344. Its totient is φ = 1932396100.

The previous prime is 2125635719. The next prime is 2125635731. The reversal of 2125635721 is 1275365212.

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 2125635721 - 2¹ = 2125635719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2125635731) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96619795 + ... + 96619816.

It is an arithmetic number, because the mean of its divisors is an integer number (579718836).

Almost surely, 2^2125635721 is an apocalyptic number.

It is an amenable number.

2125635721 is a deficient number, since it is larger than the sum of its proper divisors (193239623).

2125635721 is a wasteful number, since it uses less digits than its factorization.

2125635721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193239622.

The product of its digits is 25200, while the sum is 34.

The square root of 2125635721 is about 46104.6171332113. The cubic root of 2125635721 is about 1285.7689878566.

The spelling of 2125635721 in words is "two billion, one hundred twenty-five million, six hundred thirty-five thousand, seven hundred twenty-one".