1638143194 has 8 divisors (see below), whose sum is σ = 2461225140. Its totient is φ = 817734816.

The previous prime is 1638143189. The next prime is 1638143219. The reversal of 1638143194 is 4913418361.

It can be written as a sum of positive squares in 2 ways, for example, as 1218917569 + 419225625 = 34913^2 + 20475^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 666859 + ... + 669310.

Almost surely, 2^1638143194 is an apocalyptic number.

1638143194 is a deficient number, since it is larger than the sum of its proper divisors (823081946).

1638143194 is a wasteful number, since it uses less digits than its factorization.

1638143194 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1336784.

The product of its digits is 62208, while the sum is 40.

The square root of 1638143194 is about 40473.9816919462. The cubic root of 1638143194 is about 1178.8284825058.

The spelling of 1638143194 in words is "one billion, six hundred thirty-eight million, one hundred forty-three thousand, one hundred ninety-four".