2161612500 has 144 divisors (see below), whose sum is σ = 6417714240. Its totient is φ = 566080000.

The previous prime is 2161612489. The next prime is 2161612549. The reversal of 2161612500 is 52161612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2212012 + ... + 2212988.

It is an arithmetic number, because the mean of its divisors is an integer number (44567460).

Almost surely, 2^2161612500 is an apocalyptic number.

2161612500 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 2161612500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3208857120).

2161612500 is an abundant number, since it is smaller than the sum of its proper divisors (4256101740).

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

2161612500 is an equidigital number, since it uses as much as digits as its factorization.

2161612500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1068 (or 1046 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 2161612500 is about 46493.1446559598. The cubic root of 2161612500 is about 1292.9824030756.

The spelling of 2161612500 in words is "two billion, one hundred sixty-one million, six hundred twelve thousand, five hundred".