21551543103005 has 4 divisors (see below), whose sum is σ = 25861851723612. Its totient is φ = 17241234482400.

The previous prime is 21551543102989. The next prime is 21551543103031. The reversal of 21551543103005 is 50030134515512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10602148136836 + 10949394966169 = 3256094^2 + 3308987^2 .

It is not a de Polignac number, because 21551543103005 - 2⁴ = 21551543102989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2155154310296 + ... + 2155154310305.

It is an arithmetic number, because the mean of its divisors is an integer number (6465462930903).

Almost surely, 2^{21551543103005} is an apocalyptic number.

It is an amenable number.

21551543103005 is a deficient number, since it is larger than the sum of its proper divisors (4310308620607).

21551543103005 is an equidigital number, since it uses as much as digits as its factorization.

21551543103005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4310308620606.

The product of its (nonzero) digits is 45000, while the sum is 35.

Adding to 21551543103005 its reverse (50030134515512), we get a palindrome (71581677618517).

The spelling of 21551543103005 in words is "twenty-one trillion, five hundred fifty-one billion, five hundred forty-three million, one hundred three thousand, five".