21621533005253 has 16 divisors (see below), whose sum is σ = 21849977167872. Its totient is φ = 21394316160000.

The previous prime is 21621533005217. The next prime is 21621533005279. The reversal of 21621533005253 is 35250033512612.

It is a cyclic number.

It is not a de Polignac number, because 21621533005253 - 2⁸ = 21621533004997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21621533002253) 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, 354997103 + ... + 355058003.

It is an arithmetic number, because the mean of its divisors is an integer number (1365623572992).

Almost surely, 2^{21621533005253} is an apocalyptic number.

It is an amenable number.

21621533005253 is a deficient number, since it is larger than the sum of its proper divisors (228444162619).

21621533005253 is a wasteful number, since it uses less digits than its factorization.

21621533005253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70916.

The product of its (nonzero) digits is 162000, while the sum is 38.

Adding to 21621533005253 its reverse (35250033512612), we get a palindrome (56871566517865).

The spelling of 21621533005253 in words is "twenty-one trillion, six hundred twenty-one billion, five hundred thirty-three million, five thousand, two hundred fifty-three".