21521453203553 has 8 divisors (see below), whose sum is σ = 21524769427968. Its totient is φ = 21518137259424.

The previous prime is 21521453203531. The next prime is 21521453203559. The reversal of 21521453203553 is 35530235412512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21521453203553 - 2¹⁸ = 21521452941409 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21521453203553.

It is not an unprimeable number, because it can be changed into a prime (21521453203559) 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 7 ways as a sum of consecutive naturals, for example, 191540276 + ... + 191652602.

It is an arithmetic number, because the mean of its divisors is an integer number (2690596178496).

Almost surely, 2^{21521453203553} is an apocalyptic number.

It is an amenable number.

21521453203553 is a deficient number, since it is larger than the sum of its proper divisors (3316224415).

21521453203553 is a wasteful number, since it uses less digits than its factorization.

21521453203553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140143.

The product of its (nonzero) digits is 540000, while the sum is 41.

The spelling of 21521453203553 in words is "twenty-one trillion, five hundred twenty-one billion, four hundred fifty-three million, two hundred three thousand, five hundred fifty-three".