21145421538833 has 4 divisors (see below), whose sum is σ = 21150955544628. Its totient is φ = 21139887533040.

The previous prime is 21145421538817. The next prime is 21145421538877. The reversal of 21145421538833 is 33883512454112.

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 19066077726784 + 2079343812049 = 4366472^2 + 1441993^2 .

It is a cyclic number.

It is not a de Polignac number, because 21145421538833 - 2⁴ = 21145421538817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21145421538533) 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, 2766997166 + ... + 2767004807.

It is an arithmetic number, because the mean of its divisors is an integer number (5287738886157).

Almost surely, 2^{21145421538833} is an apocalyptic number.

It is an amenable number.

21145421538833 is a deficient number, since it is larger than the sum of its proper divisors (5534005795).

21145421538833 is an equidigital number, since it uses as much as digits as its factorization.

21145421538833 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5534005794.

The product of its digits is 2764800, while the sum is 50.

The spelling of 21145421538833 in words is "twenty-one trillion, one hundred forty-five billion, four hundred twenty-one million, five hundred thirty-eight thousand, eight hundred thirty-three".