2168123640 has 128 divisors (see below), whose sum is σ = 6706402560. Its totient is φ = 560415744.

The previous prime is 2168123627. The next prime is 2168123647. The reversal of 2168123640 is 463218612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2168123647) 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, 705387 + ... + 708453.

It is an arithmetic number, because the mean of its divisors is an integer number (52393770).

Almost surely, 2^2168123640 is an apocalyptic number.

2168123640 is a gapful number since it is divisible by the number (20) 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 2168123640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3353201280).

2168123640 is an abundant number, since it is smaller than the sum of its proper divisors (4538278920).

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

2168123640 is a wasteful number, since it uses less digits than its factorization.

2168123640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3261 (or 3257 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 2168123640 is about 46563.1145865480. The cubic root of 2168123640 is about 1294.2793284998.

The spelling of 2168123640 in words is "two billion, one hundred sixty-eight million, one hundred twenty-three thousand, six hundred forty".