21575457447 has 8 divisors (see below), whose sum is σ = 28768049280. Its totient is φ = 14383251960.

The previous prime is 21575457443. The next prime is 21575457457. The reversal of 21575457447 is 74475457512.

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

It is not a de Polignac number, because 21575457447 - 2² = 21575457443 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21575457447.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21575457443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79672 + ... + 222482.

It is an arithmetic number, because the mean of its divisors is an integer number (3596006160).

Almost surely, 2^21575457447 is an apocalyptic number.

21575457447 is a deficient number, since it is larger than the sum of its proper divisors (7192591833).

21575457447 is a wasteful number, since it uses less digits than its factorization.

21575457447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193173.

The product of its digits is 5488000, while the sum is 51.

The spelling of 21575457447 in words is "twenty-one billion, five hundred seventy-five million, four hundred fifty-seven thousand, four hundred forty-seven".