1638489819 has 8 divisors (see below), whose sum is σ = 2184862480. Its totient is φ = 1092221856.

The previous prime is 1638489799. The next prime is 1638489857. The reversal of 1638489819 is 9189848361.

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

It is not a de Polignac number, because 1638489819 - 2⁷ = 1638489691 is a prime.

It is a super-2 number, since 2×1638489819² = 5369297773933305522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1638489899) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24189 + ... + 62145.

It is an arithmetic number, because the mean of its divisors is an integer number (273107810).

Almost surely, 2^1638489819 is an apocalyptic number.

1638489819 is a deficient number, since it is larger than the sum of its proper divisors (546372661).

1638489819 is a wasteful number, since it uses less digits than its factorization.

1638489819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52349.

The product of its digits is 2985984, while the sum is 57.

The square root of 1638489819 is about 40478.2635373604. The cubic root of 1638489819 is about 1178.9116218812.

The spelling of 1638489819 in words is "one billion, six hundred thirty-eight million, four hundred eighty-nine thousand, eight hundred nineteen".