2185129021 has 2 divisors, whose sum is σ = 2185129022. Its totient is φ = 2185129020.

The previous prime is 2185128973. The next prime is 2185129031. The reversal of 2185129021 is 1209215812.

2185129021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1875756100 + 309372921 = 43310^2 + 17589^2 .

It is a cyclic number.

It is not a de Polignac number, because 2185129021 - 2¹³ = 2185120829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2185129031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1092564510 + 1092564511.

It is an arithmetic number, because the mean of its divisors is an integer number (1092564511).

Almost surely, 2^2185129021 is an apocalyptic number.

It is an amenable number.

2185129021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2185129021 is an equidigital number, since it uses as much as digits as its factorization.

2185129021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 31.

The square root of 2185129021 is about 46745.3636310597. The cubic root of 2185129021 is about 1297.6543542199.

The spelling of 2185129021 in words is "two billion, one hundred eighty-five million, one hundred twenty-nine thousand, twenty-one".