21551544401323 has 4 divisors (see below), whose sum is σ = 21575841521040. Its totient is φ = 21527247281608.

The previous prime is 21551544401273. The next prime is 21551544401383. The reversal of 21551544401323 is 32310444515512.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21551544401323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21551544401383) 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, 12148558528 + ... + 12148560301.

It is an arithmetic number, because the mean of its divisors is an integer number (5393960380260).

Almost surely, 2^{21551544401323} is an apocalyptic number.

21551544401323 is a deficient number, since it is larger than the sum of its proper divisors (24297119717).

21551544401323 is an equidigital number, since it uses as much as digits as its factorization.

21551544401323 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24297119716.

The product of its (nonzero) digits is 288000, while the sum is 40.

Adding to 21551544401323 its reverse (32310444515512), we get a palindrome (53861988916835).

The spelling of 21551544401323 in words is "twenty-one trillion, five hundred fifty-one billion, five hundred forty-four million, four hundred one thousand, three hundred twenty-three".