1638969853 has 4 divisors (see below), whose sum is σ = 1673841600. Its totient is φ = 1604098108.

The previous prime is 1638969851. The next prime is 1638969863. The reversal of 1638969853 is 3589698361.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3589698361 = 797 ⋅4504013.

It is a cyclic number.

It is not a de Polignac number, because 1638969853 - 2¹ = 1638969851 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638969851) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17435803 + ... + 17435896.

It is an arithmetic number, because the mean of its divisors is an integer number (418460400).

Almost surely, 2^1638969853 is an apocalyptic number.

It is an amenable number.

1638969853 is a deficient number, since it is larger than the sum of its proper divisors (34871747).

1638969853 is an equidigital number, since it uses as much as digits as its factorization.

1638969853 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34871746.

The product of its digits is 8398080, while the sum is 58.

The square root of 1638969853 is about 40484.1926311987. The cubic root of 1638969853 is about 1179.0267405712.

The spelling of 1638969853 in words is "one billion, six hundred thirty-eight million, nine hundred sixty-nine thousand, eight hundred fifty-three".