2001553 has 2 divisors, whose sum is σ = 2001554. Its totient is φ = 2001552.

The previous prime is 2001547. The next prime is 2001581. The reversal of 2001553 is 3551002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1979649 + 21904 = 1407^2 + 148^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2001553 is a prime.

It is not a weakly prime, because it can be changed into another prime (2001533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1000776 + 1000777.

It is an arithmetic number, because the mean of its divisors is an integer number (1000777).

2^2001553 is an apocalyptic number.

It is an amenable number.

2001553 is a deficient number, since it is larger than the sum of its proper divisors (1).

2001553 is an equidigital number, since it uses as much as digits as its factorization.

2001553 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 150, while the sum is 16.

The square root of 2001553 is about 1414.7625242421. The cubic root of 2001553 is about 126.0247075088.

Adding to 2001553 its reverse (3551002), we get a palindrome (5552555).

The spelling of 2001553 in words is "two million, one thousand, five hundred fifty-three".