20553444021521 has 16 divisors (see below), whose sum is σ = 22908096388800. Its totient is φ = 18326104178688.

The previous prime is 20553444021503. The next prime is 20553444021557. The reversal of 20553444021521 is 12512044435502.

It is a cyclic number.

It is not a de Polignac number, because 20553444021521 - 2¹⁸ = 20553443759377 is a prime.

It is a super-2 number, since 2×20553444021521² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20553444021571) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38765750 + ... + 39292368.

It is an arithmetic number, because the mean of its divisors is an integer number (1431756024300).

Almost surely, 2^{20553444021521} is an apocalyptic number.

It is an amenable number.

20553444021521 is a deficient number, since it is larger than the sum of its proper divisors (2354652367279).

20553444021521 is a wasteful number, since it uses less digits than its factorization.

20553444021521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 647488.

The product of its (nonzero) digits is 192000, while the sum is 38.

The spelling of 20553444021521 in words is "twenty trillion, five hundred fifty-three billion, four hundred forty-four million, twenty-one thousand, five hundred twenty-one".