21520616534553 has 16 divisors (see below), whose sum is σ = 29125495425600. Its totient is φ = 14131452800256.

The previous prime is 21520616534471. The next prime is 21520616534663. The reversal of 21520616534553 is 35543561602512.

It is not a de Polignac number, because 21520616534553 - 2²⁰ = 21520615485977 is a prime.

It is a super-3 number, since 3×21520616534553³ (a number of 41 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21520616524553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3728028 + ... + 7545821.

It is an arithmetic number, because the mean of its divisors is an integer number (1820343464100).

Almost surely, 2^{21520616534553} is an apocalyptic number.

It is an amenable number.

21520616534553 is a deficient number, since it is larger than the sum of its proper divisors (7604878891047).

21520616534553 is a wasteful number, since it uses less digits than its factorization.

21520616534553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11283416.

The product of its (nonzero) digits is 3240000, while the sum is 48.

The spelling of 21520616534553 in words is "twenty-one trillion, five hundred twenty billion, six hundred sixteen million, five hundred thirty-four thousand, five hundred fifty-three".