21404427571 has 8 divisors (see below), whose sum is σ = 21441700800. Its totient is φ = 21367188480.

The previous prime is 21404427529. The next prime is 21404427593. The reversal of 21404427571 is 17572440412.

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

It is a cyclic number.

It is not a de Polignac number, because 21404427571 - 2³³ = 12814492979 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21404427571.

It is not an unprimeable number, because it can be changed into a prime (21404427871) 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, 1456641 + ... + 1471261.

It is an arithmetic number, because the mean of its divisors is an integer number (2680212600).

Almost surely, 2^21404427571 is an apocalyptic number.

21404427571 is a deficient number, since it is larger than the sum of its proper divisors (37273229).

21404427571 is a wasteful number, since it uses less digits than its factorization.

21404427571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17069.

The product of its (nonzero) digits is 62720, while the sum is 37.

Adding to 21404427571 its reverse (17572440412), we get a palindrome (38976867983).

The spelling of 21404427571 in words is "twenty-one billion, four hundred four million, four hundred twenty-seven thousand, five hundred seventy-one".