2156511443220 has 144 divisors (see below), whose sum is σ = 6722202614400. Its totient is φ = 559195031808.

The previous prime is 2156511443189. The next prime is 2156511443291. The reversal of 2156511443220 is 223441156512.

2156511443220 is a `hidden beast` number, since 2 + 1 + 56 + 511 + 44 + 32 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11220049 + ... + 11410631.

It is an arithmetic number, because the mean of its divisors is an integer number (46681962600).

Almost surely, 2^{2156511443220} is an apocalyptic number.

2156511443220 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 2156511443220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3361101307200).

2156511443220 is an abundant number, since it is smaller than the sum of its proper divisors (4565691171180).

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

2156511443220 is a wasteful number, since it uses less digits than its factorization.

2156511443220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 192334 (or 192329 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

Adding to 2156511443220 its reverse (223441156512), we get a palindrome (2379952599732).

The spelling of 2156511443220 in words is "two trillion, one hundred fifty-six billion, five hundred eleven million, four hundred forty-three thousand, two hundred twenty".