21055008447 has 12 divisors (see below), whose sum is σ = 33177589224. Its totient is φ = 12760611120.

The previous prime is 21055008439. The next prime is 21055008449. The reversal of 21055008447 is 74480055012.

21055008447 is a `hidden beast` number, since 2 + 105 + 500 + 8 + 4 + 47 = 666.

It is not a de Polignac number, because 21055008447 - 2³ = 21055008439 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21055008449) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 106338328 + ... + 106338525.

It is an arithmetic number, because the mean of its divisors is an integer number (2764799102).

Almost surely, 2^21055008447 is an apocalyptic number.

21055008447 is a deficient number, since it is larger than the sum of its proper divisors (12122580777).

21055008447 is a wasteful number, since it uses less digits than its factorization.

21055008447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 212676870 (or 212676867 counting only the distinct ones).

The product of its (nonzero) digits is 44800, while the sum is 36.

The spelling of 21055008447 in words is "twenty-one billion, fifty-five million, eight thousand, four hundred forty-seven".