21253044261613 has 16 divisors (see below), whose sum is σ = 22573387972800. Its totient is φ = 19953644613120.

The previous prime is 21253044261611. The next prime is 21253044261619. The reversal of 21253044261613 is 31616244035212.

It is a cyclic number.

It is not a de Polignac number, because 21253044261613 - 2¹ = 21253044261611 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253044261611) 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 15 ways as a sum of consecutive naturals, for example, 9667428 + ... + 11660413.

It is an arithmetic number, because the mean of its divisors is an integer number (1410836748300).

Almost surely, 2^{21253044261613} is an apocalyptic number.

It is an amenable number.

21253044261613 is a deficient number, since it is larger than the sum of its proper divisors (1320343711187).

21253044261613 is a wasteful number, since it uses less digits than its factorization.

21253044261613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21328332.

The product of its (nonzero) digits is 207360, while the sum is 40.

Adding to 21253044261613 its reverse (31616244035212), we get a palindrome (52869288296825).

The spelling of 21253044261613 in words is "twenty-one trillion, two hundred fifty-three billion, forty-four million, two hundred sixty-one thousand, six hundred thirteen".