21550433312455 has 4 divisors (see below), whose sum is σ = 25860519974952. Its totient is φ = 17240346649960.

The previous prime is 21550433312449. The next prime is 21550433312459. The reversal of 21550433312455 is 55421333405512.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-21550433312455 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 (21550433312459) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2155043331241 + ... + 2155043331250.

It is an arithmetic number, because the mean of its divisors is an integer number (6465129993738).

Almost surely, 2^{21550433312455} is an apocalyptic number.

21550433312455 is a deficient number, since it is larger than the sum of its proper divisors (4310086662497).

21550433312455 is an equidigital number, since it uses as much as digits as its factorization.

21550433312455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4310086662496.

The product of its (nonzero) digits is 1080000, while the sum is 43.

Adding to 21550433312455 its reverse (55421333405512), we get a palindrome (76971766717967).

The spelling of 21550433312455 in words is "twenty-one trillion, five hundred fifty billion, four hundred thirty-three million, three hundred twelve thousand, four hundred fifty-five".