1638168373 has 2 divisors, whose sum is σ = 1638168374. Its totient is φ = 1638168372.

The previous prime is 1638168299. The next prime is 1638168397. The reversal of 1638168373 is 3738618361.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1613387889 + 24780484 = 40167^2 + 4978^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638168373 - 2¹⁷ = 1638037301 is a prime.

It is a super-3 number, since 3×1638168373³ (a number of 29 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1638168173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819084186 + 819084187.

It is an arithmetic number, because the mean of its divisors is an integer number (819084187).

Almost surely, 2^1638168373 is an apocalyptic number.

It is an amenable number.

1638168373 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638168373 is an equidigital number, since it uses as much as digits as its factorization.

1638168373 is an evil number, because the sum of its binary digits is even.

The product of its digits is 435456, while the sum is 46.

The square root of 1638168373 is about 40474.2927424310. The cubic root of 1638168373 is about 1178.8345221834.

The spelling of 1638168373 in words is "one billion, six hundred thirty-eight million, one hundred sixty-eight thousand, three hundred seventy-three".