1638441897 has 8 divisors (see below), whose sum is σ = 2206219200. Its totient is φ = 1081479600.

The previous prime is 1638441863. The next prime is 1638441899. The reversal of 1638441897 is 7981448361.

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

It is not a de Polignac number, because 1638441897 - 2⁷ = 1638441769 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1638441899) 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, 2703397 + ... + 2704002.

It is an arithmetic number, because the mean of its divisors is an integer number (275777400).

Almost surely, 2^1638441897 is an apocalyptic number.

It is an amenable number.

1638441897 is a deficient number, since it is larger than the sum of its proper divisors (567777303).

1638441897 is a wasteful number, since it uses less digits than its factorization.

1638441897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5407503.

The product of its digits is 1161216, while the sum is 51.

The square root of 1638441897 is about 40477.6715857027. The cubic root of 1638441897 is about 1178.9001282988.

The spelling of 1638441897 in words is "one billion, six hundred thirty-eight million, four hundred forty-one thousand, eight hundred ninety-seven".