1638913 has 2 divisors, whose sum is σ = 1638914. Its totient is φ = 1638912.

The previous prime is 1638907. The next prime is 1638929. The reversal of 1638913 is 3198361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 986049 + 652864 = 993^2 + 808^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638913 - 2¹³ = 1630721 is a prime.

It is not a weakly prime, because it can be changed into another prime (1638943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819456 + 819457.

It is an arithmetic number, because the mean of its divisors is an integer number (819457).

2^1638913 is an apocalyptic number.

It is an amenable number.

1638913 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638913 is an equidigital number, since it uses as much as digits as its factorization.

1638913 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3888, while the sum is 31.

The square root of 1638913 is about 1280.2003749414. The cubic root of 1638913 is about 117.9013107621.

The spelling of 1638913 in words is "one million, six hundred thirty-eight thousand, nine hundred thirteen".