2158517840 has 80 divisors (see below), whose sum is σ = 5170835712. Its totient is φ = 837361152.

The previous prime is 2158517839. The next prime is 2158517849. The reversal of 2158517840 is 487158512.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2158517849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1085327 + ... + 1087313.

Almost surely, 2^2158517840 is an apocalyptic number.

2158517840 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 2158517840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2585417856).

2158517840 is an abundant number, since it is smaller than the sum of its proper divisors (3012317872).

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

2158517840 is a wasteful number, since it uses less digits than its factorization.

2158517840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2404 (or 2398 counting only the distinct ones).

The product of its (nonzero) digits is 89600, while the sum is 41.

The square root of 2158517840 is about 46459.8519153903. The cubic root of 2158517840 is about 1292.3650781323.

The spelling of 2158517840 in words is "two billion, one hundred fifty-eight million, five hundred seventeen thousand, eight hundred forty".