2161861620 has 48 divisors (see below), whose sum is σ = 6121241280. Its totient is φ = 570017536.

The previous prime is 2161861619. The next prime is 2161861631. The reversal of 2161861620 is 261681612.

2161861620 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 197082 + ... + 207761.

It is an arithmetic number, because the mean of its divisors is an integer number (127525860).

Almost surely, 2^2161861620 is an apocalyptic number.

2161861620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2161861620 is an abundant number, since it is smaller than the sum of its proper divisors (3959379660).

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

2161861620 is a wasteful number, since it uses less digits than its factorization.

2161861620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404944 (or 404942 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 2161861620 is about 46495.8236834234. The cubic root of 2161861620 is about 1293.0320720771.

It can be divided in two parts, 21618 and 61620, that added together give a palindrome (83238).

The spelling of 2161861620 in words is "two billion, one hundred sixty-one million, eight hundred sixty-one thousand, six hundred twenty".