21531147277361 has 4 divisors (see below), whose sum is σ = 21937395339252. Its totient is φ = 21124899215472.

The previous prime is 21531147277357. The next prime is 21531147277369. The reversal of 21531147277361 is 16377274113512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16659662640625 + 4871484636736 = 4081625^2 + 2207144^2 .

It is a cyclic number.

It is not a de Polignac number, because 21531147277361 - 2² = 21531147277357 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21531147277369) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 203124030866 + ... + 203124030971.

It is an arithmetic number, because the mean of its divisors is an integer number (5484348834813).

Almost surely, 2^{21531147277361} is an apocalyptic number.

It is an amenable number.

21531147277361 is a deficient number, since it is larger than the sum of its proper divisors (406248061891).

21531147277361 is an equidigital number, since it uses as much as digits as its factorization.

21531147277361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 406248061890.

The product of its digits is 1481760, while the sum is 50.

The spelling of 21531147277361 in words is "twenty-one trillion, five hundred thirty-one billion, one hundred forty-seven million, two hundred seventy-seven thousand, three hundred sixty-one".