21520005253353 has 24 divisors (see below), whose sum is σ = 32219641653888. Its totient is φ = 13831848388512.

The previous prime is 21520005253333. The next prime is 21520005253399. The reversal of 21520005253353 is 35335250002512.

21520005253353 is a `hidden beast` number, since 2 + 1 + 5 + 20 + 0 + 0 + 52 + 533 + 53 = 666.

It is not a de Polignac number, because 21520005253353 - 2⁵ = 21520005253321 is a prime.

It is a super-2 number, since 2×21520005253353² (a number of 27 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21520005253333) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 379633726 + ... + 379690407.

It is an arithmetic number, because the mean of its divisors is an integer number (1342485068912).

Almost surely, 2^{21520005253353} is an apocalyptic number.

It is an amenable number.

21520005253353 is a deficient number, since it is larger than the sum of its proper divisors (10699636400535).

21520005253353 is a wasteful number, since it uses less digits than its factorization.

21520005253353 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 759324253 (or 759324250 counting only the distinct ones).

The product of its (nonzero) digits is 135000, while the sum is 36.

Adding to 21520005253353 its reverse (35335250002512), we get a palindrome (56855255255865).

The spelling of 21520005253353 in words is "twenty-one trillion, five hundred twenty billion, five million, two hundred fifty-three thousand, three hundred fifty-three".