1638894312 has 144 divisors (see below), whose sum is σ = 4967202240. Its totient is φ = 484128000.

The previous prime is 1638894293. The next prime is 1638894319. The reversal of 1638894312 is 2134988361.

1638894312 is a `hidden beast` number, since 1 + 638 + 8 + 9 + 4 + 3 + 1 + 2 = 666.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (1638894319) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1330737 + ... + 1331967.

It is an arithmetic number, because the mean of its divisors is an integer number (34494460).

Almost surely, 2^1638894312 is an apocalyptic number.

1638894312 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1638894312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2483601120).

1638894312 is an abundant number, since it is smaller than the sum of its proper divisors (3328307928).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1638894312 is a wasteful number, since it uses less digits than its factorization.

1638894312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1336 (or 1288 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 1638894312 is about 40483.2596513670. The cubic root of 1638894312 is about 1179.0086263011.

The spelling of 1638894312 in words is "one billion, six hundred thirty-eight million, eight hundred ninety-four thousand, three hundred twelve".