1005251921 has 2 divisors, whose sum is σ = 1005251922. Its totient is φ = 1005251920.

The previous prime is 1005251917. The next prime is 1005251959. The reversal of 1005251921 is 1291525001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 997612225 + 7639696 = 31585^2 + 2764^2 .

It is a cyclic number.

It is not a de Polignac number, because 1005251921 - 2² = 1005251917 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 (1005251521) 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, 502625960 + 502625961.

It is an arithmetic number, because the mean of its divisors is an integer number (502625961).

Almost surely, 2^1005251921 is an apocalyptic number.

It is an amenable number.

1005251921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1005251921 is an equidigital number, since it uses as much as digits as its factorization.

1005251921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 900, while the sum is 26.

The square root of 1005251921 is about 31705.7080192195. The cubic root of 1005251921 is about 1001.7475845027.

Adding to 1005251921 its reverse (1291525001), we get a palindrome (2296776922).

The spelling of 1005251921 in words is "one billion, five million, two hundred fifty-one thousand, nine hundred twenty-one".