2125231921 has 2 divisors, whose sum is σ = 2125231922. Its totient is φ = 2125231920.

The previous prime is 2125231919. The next prime is 2125231949. The reversal of 2125231921 is 1291325212.

It is an a-pointer prime, because the next prime (2125231949) can be obtained adding 2125231921 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2038071025 + 87160896 = 45145^2 + 9336^2 .

It is a cyclic number.

It is not a de Polignac number, because 2125231921 - 2¹ = 2125231919 is a prime.

It is a super-4 number, since 4×2125231921⁴ (a number of 38 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

Together with 2125231919, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 2125231921.

It is not a weakly prime, because it can be changed into another prime (2125231961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1062615960 + 1062615961.

It is an arithmetic number, because the mean of its divisors is an integer number (1062615961).

Almost surely, 2^2125231921 is an apocalyptic number.

It is an amenable number.

2125231921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2125231921 is an equidigital number, since it uses as much as digits as its factorization.

2125231921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 28.

The square root of 2125231921 is about 46100.2377542676. The cubic root of 2125231921 is about 1285.6875649373.

The spelling of 2125231921 in words is "two billion, one hundred twenty-five million, two hundred thirty-one thousand, nine hundred twenty-one".