21056545155855 has 64 divisors (see below), whose sum is σ = 38044416960000. Its totient is φ = 9851015569920.

The previous prime is 21056545155853. The next prime is 21056545155859. The reversal of 21056545155855 is 55855154565012.

It is not a de Polignac number, because 21056545155855 - 2¹ = 21056545155853 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21056545155795 and 21056545155804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056545155853) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6263896 + ... + 9019394.

It is an arithmetic number, because the mean of its divisors is an integer number (594444015000).

Almost surely, 2^{21056545155855} is an apocalyptic number.

21056545155855 is a deficient number, since it is larger than the sum of its proper divisors (16987871804145).

21056545155855 is a wasteful number, since it uses less digits than its factorization.

21056545155855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2757144.

The product of its (nonzero) digits is 30000000, while the sum is 57.

The spelling of 21056545155855 in words is "twenty-one trillion, fifty-six billion, five hundred forty-five million, one hundred fifty-five thousand, eight hundred fifty-five".