21045042771 has 8 divisors (see below), whose sum is σ = 28071705024. Its totient is φ = 14024204520.

The previous prime is 21045042769. The next prime is 21045042791. The reversal of 21045042771 is 17724054012.

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

It is not a de Polignac number, because 21045042771 - 2¹ = 21045042769 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21045042721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1447561 + ... + 1462026.

It is an arithmetic number, because the mean of its divisors is an integer number (3508963128).

Almost surely, 2^21045042771 is an apocalyptic number.

21045042771 is a deficient number, since it is larger than the sum of its proper divisors (7026662253).

21045042771 is a wasteful number, since it uses less digits than its factorization.

21045042771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2912001.

The product of its (nonzero) digits is 15680, while the sum is 33.

Adding to 21045042771 its reverse (17724054012), we get a palindrome (38769096783).

The spelling of 21045042771 in words is "twenty-one billion, forty-five million, forty-two thousand, seven hundred seventy-one".