21556187035271 has 16 divisors (see below), whose sum is σ = 24674431038720. Its totient is φ = 18447651270720.

The previous prime is 21556187035267. The next prime is 21556187035289. The reversal of 21556187035271 is 17253078165512.

It is a happy number.

It is not a de Polignac number, because 21556187035271 - 2² = 21556187035267 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21556187031271) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23063411 + ... + 23979851.

It is an arithmetic number, because the mean of its divisors is an integer number (1542151939920).

Almost surely, 2^{21556187035271} is an apocalyptic number.

21556187035271 is a deficient number, since it is larger than the sum of its proper divisors (3118244003449).

21556187035271 is an equidigital number, since it uses as much as digits as its factorization.

21556187035271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 921734.

The product of its (nonzero) digits is 3528000, while the sum is 53.

The spelling of 21556187035271 in words is "twenty-one trillion, five hundred fifty-six billion, one hundred eighty-seven million, thirty-five thousand, two hundred seventy-one".