2181172136 has 144 divisors (see below), whose sum is σ = 4965156000. Its totient is φ = 896987520.

The previous prime is 2181172129. The next prime is 2181172141. The reversal of 2181172136 is 6312711812.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 10960565 + ... + 10960763.

It is an arithmetic number, because the mean of its divisors is an integer number (34480250).

Almost surely, 2^2181172136 is an apocalyptic number.

2181172136 is a gapful number since it is divisible by the number (26) 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 2181172136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2482578000).

2181172136 is an abundant number, since it is smaller than the sum of its proper divisors (2783983864).

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

2181172136 is a wasteful number, since it uses less digits than its factorization.

2181172136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320 (or 292 counting only the distinct ones).

The product of its digits is 4032, while the sum is 32.

The square root of 2181172136 is about 46703.0206303618. The cubic root of 2181172136 is about 1296.8706062200.

Adding to 2181172136 its reverse (6312711812), we get a palindrome (8493883948).

The spelling of 2181172136 in words is "two billion, one hundred eighty-one million, one hundred seventy-two thousand, one hundred thirty-six".