21154535621105 has 8 divisors (see below), whose sum is σ = 25386446234664. Its totient is φ = 16922959504000.

The previous prime is 21154535621077. The next prime is 21154535621123. The reversal of 21154535621105 is 50112653545112.

It can be written as a sum of positive squares in 4 ways, for example, as 138032311729 + 21016503309376 = 371527^2 + 4584376^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21154535621105 - 2⁸ = 21154535620849 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 83484956 + ... + 83737965.

It is an arithmetic number, because the mean of its divisors is an integer number (3173305779333).

Almost surely, 2^{21154535621105} is an apocalyptic number.

It is an amenable number.

21154535621105 is a deficient number, since it is larger than the sum of its proper divisors (4231910613559).

21154535621105 is a wasteful number, since it uses less digits than its factorization.

21154535621105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167248227.

The product of its (nonzero) digits is 180000, while the sum is 41.

The spelling of 21154535621105 in words is "twenty-one trillion, one hundred fifty-four billion, five hundred thirty-five million, six hundred twenty-one thousand, one hundred five".