2154721894560 has 144 divisors (see below), whose sum is σ = 7551718069896. Its totient is φ = 559062964224.

The previous prime is 2154721894531. The next prime is 2154721894603. The reversal of 2154721894560 is 654981274512.

2154721894560 is a `hidden beast` number, since 2 + 1 + 5 + 4 + 7 + 2 + 189 + 456 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2130910935696 + 23810958864 = 1459764^2 + 154308^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a junction number, because it is equal to n+sod(n) for n = 2154721894497 and 2154721894506.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20167459 + ... + 20274018.

Almost surely, 2^{2154721894560} is an apocalyptic number.

2154721894560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2154721894560 is an abundant number, since it is smaller than the sum of its proper divisors (5396996175336).

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

2154721894560 is a wasteful number, since it uses less digits than its factorization.

2154721894560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40441535 (or 40441524 counting only the distinct ones).

The product of its (nonzero) digits is 4838400, while the sum is 54.

The spelling of 2154721894560 in words is "two trillion, one hundred fifty-four billion, seven hundred twenty-one million, eight hundred ninety-four thousand, five hundred sixty".