2161872726440 has 192 divisors, whose sum is σ = 5781917116800. Its totient is φ = 725189337600.

The previous prime is 2161872726367. The next prime is 2161872726443. The reversal of 2161872726440 is 446272781612.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (2161872726443) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 18170666 + ... + 18289254.

It is an arithmetic number, because the mean of its divisors is an integer number (30114151650).

Almost surely, 2^{2161872726440} is an apocalyptic number.

2161872726440 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 2161872726440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2890958558400).

2161872726440 is an abundant number, since it is smaller than the sum of its proper divisors (3620044390360).

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

2161872726440 is a wasteful number, since it uses less digits than its factorization.

2161872726440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118816 (or 118805 counting only the distinct ones).

The product of its (nonzero) digits is 1806336, while the sum is 50.

The spelling of 2161872726440 in words is "two trillion, one hundred sixty-one billion, eight hundred seventy-two million, seven hundred twenty-six thousand, four hundred forty".