21027145054561 has 4 divisors (see below), whose sum is σ = 21027883836672. Its totient is φ = 21026406272452.

The previous prime is 21027145054549. The next prime is 21027145054579. The reversal of 21027145054561 is 16545054172012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21027145054561 - 2¹⁷ = 21027144923489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21027145055561) 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, 369348361 + ... + 369405286.

It is an arithmetic number, because the mean of its divisors is an integer number (5256970959168).

Almost surely, 2^{21027145054561} is an apocalyptic number.

It is an amenable number.

21027145054561 is a deficient number, since it is larger than the sum of its proper divisors (738782111).

21027145054561 is an equidigital number, since it uses as much as digits as its factorization.

21027145054561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 738782110.

The product of its (nonzero) digits is 336000, while the sum is 43.

The spelling of 21027145054561 in words is "twenty-one trillion, twenty-seven billion, one hundred forty-five million, fifty-four thousand, five hundred sixty-one".