1638225624 has 128 divisors (see below), whose sum is σ = 4858560000. Its totient is φ = 459994752.

The previous prime is 1638225599. The next prime is 1638225629. The reversal of 1638225624 is 4265228361.

It is a Cunningham number, because it is equal to 40475²-1.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638225629) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 484002 + ... + 487374.

It is an arithmetic number, because the mean of its divisors is an integer number (37957500).

Almost surely, 2^1638225624 is an apocalyptic number.

1638225624 is a gapful number since it is divisible by the number (14) 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 1638225624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2429280000).

1638225624 is an abundant number, since it is smaller than the sum of its proper divisors (3220334376).

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

1638225624 is a wasteful number, since it uses less digits than its factorization.

1638225624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3462 (or 3444 counting only the distinct ones).

The product of its digits is 138240, while the sum is 39.

The square root of 1638225624 is about 40474.9999876467. Note that the first 4 decimals coincide. The cubic root of 1638225624 is about 1178.8482547297.

The spelling of 1638225624 in words is "one billion, six hundred thirty-eight million, two hundred twenty-five thousand, six hundred twenty-four".