21005242555305 has 32 divisors (see below), whose sum is σ = 34112680654464. Its totient is φ = 11034724732416.

The previous prime is 21005242555261. The next prime is 21005242555313. The reversal of 21005242555305 is 50355524250012.

It is not a de Polignac number, because 21005242555305 - 2²⁰ = 21005241506729 is a prime.

It is a super-2 number, since 2×21005242555305² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12104197 + ... + 13730333.

It is an arithmetic number, because the mean of its divisors is an integer number (1066021270452).

Almost surely, 2^{21005242555305} is an apocalyptic number.

It is an amenable number.

21005242555305 is a deficient number, since it is larger than the sum of its proper divisors (13107438099159).

21005242555305 is a wasteful number, since it uses less digits than its factorization.

21005242555305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1639065.

The product of its (nonzero) digits is 300000, while the sum is 39.

The spelling of 21005242555305 in words is "twenty-one trillion, five billion, two hundred forty-two million, five hundred fifty-five thousand, three hundred five".