1638888489 has 48 divisors (see below), whose sum is σ = 2763171840. Its totient is φ = 916673760.

The previous prime is 1638888479. The next prime is 1638888497. The reversal of 1638888489 is 9848888361.

It is not a de Polignac number, because 1638888489 - 2⁴ = 1638888473 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (1638888479) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1006494 + ... + 1008120.

It is an arithmetic number, because the mean of its divisors is an integer number (57566080).

Almost surely, 2^1638888489 is an apocalyptic number.

It is an amenable number.

1638888489 is a deficient number, since it is larger than the sum of its proper divisors (1124283351).

1638888489 is a wasteful number, since it uses less digits than its factorization.

1638888489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1970 (or 1967 counting only the distinct ones).

The product of its digits is 21233664, while the sum is 63.

The square root of 1638888489 is about 40483.1877326873. The cubic root of 1638888489 is about 1179.0072299582.

The spelling of 1638888489 in words is "one billion, six hundred thirty-eight million, eight hundred eighty-eight thousand, four hundred eighty-nine".