21205453344555 has 8 divisors (see below), whose sum is σ = 33928725351312. Its totient is φ = 11309575117088.

The previous prime is 21205453344463. The next prime is 21205453344563. The reversal of 21205453344555 is 55544335450212.

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 21205453344555 - 2²⁸ = 21205184909099 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 706848444804 + ... + 706848444833.

It is an arithmetic number, because the mean of its divisors is an integer number (4241090668914).

Almost surely, 2^{21205453344555} is an apocalyptic number.

21205453344555 is a deficient number, since it is larger than the sum of its proper divisors (12723272006757).

21205453344555 is a wasteful number, since it uses less digits than its factorization.

21205453344555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1413696889645.

The product of its (nonzero) digits is 7200000, while the sum is 48.

Adding to 21205453344555 its reverse (55544335450212), we get a palindrome (76749788794767).

The spelling of 21205453344555 in words is "twenty-one trillion, two hundred five billion, four hundred fifty-three million, three hundred forty-four thousand, five hundred fifty-five".