21375127315021 has 4 divisors (see below), whose sum is σ = 21564287733852. Its totient is φ = 21185966896192.

The previous prime is 21375127314997. The next prime is 21375127315027. The reversal of 21375127315021 is 12051372157312.

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 139491045225 + 21235636269796 = 373485^2 + 4608214^2 .

It is a cyclic number.

It is not a de Polignac number, because 21375127315021 - 2¹⁹ = 21375126790733 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 (21375127315027) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 94580209246 + ... + 94580209471.

It is an arithmetic number, because the mean of its divisors is an integer number (5391071933463).

Almost surely, 2^{21375127315021} is an apocalyptic number.

It is an amenable number.

21375127315021 is a deficient number, since it is larger than the sum of its proper divisors (189160418831).

21375127315021 is a wasteful number, since it uses less digits than its factorization.

21375127315021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189160418830.

The product of its (nonzero) digits is 88200, while the sum is 40.

The spelling of 21375127315021 in words is "twenty-one trillion, three hundred seventy-five billion, one hundred twenty-seven million, three hundred fifteen thousand, twenty-one".