21356144174545 has 8 divisors (see below), whose sum is σ = 25671787870824. Its totient is φ = 17055305432064.

The previous prime is 21356144174513. The next prime is 21356144174551. The reversal of 21356144174545 is 54547144165312.

It can be written as a sum of positive squares in 4 ways, for example, as 10920427424449 + 10435716750096 = 3304607^2 + 3230436^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21356144174545 - 2⁵ = 21356144174513 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21356144174492 and 21356144174501.

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 7 ways as a sum of consecutive naturals, for example, 3701235274 + ... + 3701241043.

It is an arithmetic number, because the mean of its divisors is an integer number (3208973483853).

Almost surely, 2^{21356144174545} is an apocalyptic number.

It is an amenable number.

21356144174545 is a deficient number, since it is larger than the sum of its proper divisors (4315643696279).

21356144174545 is an equidigital number, since it uses as much as digits as its factorization.

21356144174545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7402476899.

The product of its digits is 8064000, while the sum is 52.

The spelling of 21356144174545 in words is "twenty-one trillion, three hundred fifty-six billion, one hundred forty-four million, one hundred seventy-four thousand, five hundred forty-five".