1638673 has 2 divisors, whose sum is σ = 1638674. Its totient is φ = 1638672.

The previous prime is 1638653. The next prime is 1638677. The reversal of 1638673 is 3768361.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 944784 + 693889 = 972^2 + 833^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638673 - 2⁵ = 1638641 is a prime.

It is not a weakly prime, because it can be changed into another prime (1638677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819336 + 819337.

It is an arithmetic number, because the mean of its divisors is an integer number (819337).

2^1638673 is an apocalyptic number.

It is an amenable number.

1638673 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638673 is an equidigital number, since it uses as much as digits as its factorization.

1638673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 34.

The square root of 1638673 is about 1280.1066361831. The cubic root of 1638673 is about 117.8955553832.

Subtracting from 1638673 its product of digits (18144), we obtain a square (1620529 = 1273²).

It can be divided in two parts, 163 and 8673, that added together give a square (8836 = 94²).

The spelling of 1638673 in words is "one million, six hundred thirty-eight thousand, six hundred seventy-three".