21551440355305 has 32 divisors (see below), whose sum is σ = 29984833663488. Its totient is φ = 14564014886400.

The previous prime is 21551440355303. The next prime is 21551440355311. The reversal of 21551440355305 is 50355304415512.

It is not a de Polignac number, because 21551440355305 - 2¹ = 21551440355303 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21551440355303) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4289439 + ... + 7842331.

It is an arithmetic number, because the mean of its divisors is an integer number (937026051984).

Almost surely, 2^{21551440355305} is an apocalyptic number.

It is an amenable number.

21551440355305 is a deficient number, since it is larger than the sum of its proper divisors (8433393308183).

21551440355305 is a wasteful number, since it uses less digits than its factorization.

21551440355305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3555417.

The product of its (nonzero) digits is 900000, while the sum is 43.

The spelling of 21551440355305 in words is "twenty-one trillion, five hundred fifty-one billion, four hundred forty million, three hundred fifty-five thousand, three hundred five".