1629181638 has 96 divisors (see below), whose sum is σ = 4496394240. Its totient is φ = 415031040.

The previous prime is 1629181637. The next prime is 1629181643. The reversal of 1629181638 is 8361819261.

1629181638 is a `hidden beast` number, since 1 + 6 + 2 + 9 + 1 + 8 + 1 + 638 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 1629181593 and 1629181602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1629181637) 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, 20683 + ... + 60713.

It is an arithmetic number, because the mean of its divisors is an integer number (46837440).

Almost surely, 2^1629181638 is an apocalyptic number.

1629181638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1629181638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2248197120).

1629181638 is an abundant number, since it is smaller than the sum of its proper divisors (2867212602).

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

1629181638 is a wasteful number, since it uses less digits than its factorization.

1629181638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40082 (or 40079 counting only the distinct ones).

The product of its digits is 124416, while the sum is 45.

The square root of 1629181638 is about 40363.1222528684. The cubic root of 1629181638 is about 1176.6749344794.

The spelling of 1629181638 in words is "one billion, six hundred twenty-nine million, one hundred eighty-one thousand, six hundred thirty-eight".