2161887840 has 384 divisors, whose sum is σ = 8830080000. Its totient is φ = 493807104.

The previous prime is 2161887809. The next prime is 2161887857. The reversal of 2161887840 is 487881612.

2161887840 is a `hidden beast` number, since 21 + 618 + 8 + 7 + 8 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1481031 + ... + 1482489.

It is an arithmetic number, because the mean of its divisors is an integer number (22995000).

Almost surely, 2^2161887840 is an apocalyptic number.

2161887840 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 2161887840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4415040000).

2161887840 is an abundant number, since it is smaller than the sum of its proper divisors (6668192160).

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

2161887840 is a wasteful number, since it uses less digits than its factorization.

2161887840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1504 (or 1476 counting only the distinct ones).

The product of its (nonzero) digits is 172032, while the sum is 45.

The square root of 2161887840 is about 46496.1056433762. The cubic root of 2161887840 is about 1293.0372995415.

The spelling of 2161887840 in words is "two billion, one hundred sixty-one million, eight hundred eighty-seven thousand, eight hundred forty".