2028731921 has 2 divisors, whose sum is σ = 2028731922. Its totient is φ = 2028731920.

The previous prime is 2028731879. The next prime is 2028731993. The reversal of 2028731921 is 1291378202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2028601600 + 130321 = 45040^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 2028731921 - 2⁶ = 2028731857 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (2028701921) 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, 1014365960 + 1014365961.

It is an arithmetic number, because the mean of its divisors is an integer number (1014365961).

Almost surely, 2^2028731921 is an apocalyptic number.

It is an amenable number.

2028731921 is a deficient number, since it is larger than the sum of its proper divisors (1).

2028731921 is an equidigital number, since it uses as much as digits as its factorization.

2028731921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 2028731921 is about 45041.4467018989. The cubic root of 2028731921 is about 1265.9257121359.

The spelling of 2028731921 in words is "two billion, twenty-eight million, seven hundred thirty-one thousand, nine hundred twenty-one".