2005897921 has 4 divisors (see below), whose sum is σ = 2009499732. Its totient is φ = 2002296112.

The previous prime is 2005897903. The next prime is 2005897937. The reversal of 2005897921 is 1297985002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 658640896 + 1347257025 = 25664^2 + 36705^2 .

It is a cyclic number.

It is not a de Polignac number, because 2005897921 - 2⁹ = 2005897409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2005897951) 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, 1800070 + ... + 1801183.

It is an arithmetic number, because the mean of its divisors is an integer number (502374933).

Almost surely, 2^2005897921 is an apocalyptic number.

It is an amenable number.

2005897921 is a deficient number, since it is larger than the sum of its proper divisors (3601811).

2005897921 is an equidigital number, since it uses as much as digits as its factorization.

2005897921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3601810.

The product of its (nonzero) digits is 90720, while the sum is 43.

The square root of 2005897921 is about 44787.2517687790. The cubic root of 2005897921 is about 1261.1583202733.

The spelling of 2005897921 in words is "two billion, five million, eight hundred ninety-seven thousand, nine hundred twenty-one".