21054555505 has 16 divisors (see below), whose sum is σ = 26767120464. Its totient is φ = 15843686400.

The previous prime is 21054555433. The next prime is 21054555551. The reversal of 21054555505 is 50555545012.

It can be written as a sum of positive squares in 8 ways, for example, as 178062336 + 20876493169 = 13344^2 + 144487^2 .

It is not a de Polignac number, because 21054555505 - 2⁹ = 21054554993 is a prime.

It is a super-3 number, since 3×21054555505³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78355 + ... + 219655.

It is an arithmetic number, because the mean of its divisors is an integer number (1672945029).

Almost surely, 2^21054555505 is an apocalyptic number.

It is an amenable number.

21054555505 is a deficient number, since it is larger than the sum of its proper divisors (5712564959).

21054555505 is a wasteful number, since it uses less digits than its factorization.

21054555505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143076.

The product of its (nonzero) digits is 125000, while the sum is 37.

The spelling of 21054555505 in words is "twenty-one billion, fifty-four million, five hundred fifty-five thousand, five hundred five".