1638797 has 2 divisors, whose sum is σ = 1638798. Its totient is φ = 1638796.

The previous prime is 1638743. The next prime is 1638799. The reversal of 1638797 is 7978361.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1394761 + 244036 = 1181^2 + 494^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638797 - 2⁶ = 1638733 is a prime.

Together with 1638799, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1638799) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819398 + 819399.

It is an arithmetic number, because the mean of its divisors is an integer number (819399).

2^1638797 is an apocalyptic number.

It is an amenable number.

1638797 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638797 is an equidigital number, since it uses as much as digits as its factorization.

1638797 is an evil number, because the sum of its binary digits is even.

The product of its digits is 63504, while the sum is 41.

The square root of 1638797 is about 1280.1550687319. The cubic root of 1638797 is about 117.8985290658.

The spelling of 1638797 in words is "one million, six hundred thirty-eight thousand, seven hundred ninety-seven".