21045042764 has 24 divisors (see below), whose sum is σ = 39058917408. Its totient is φ = 9887374080.

The previous prime is 21045042721. The next prime is 21045042769. The reversal of 21045042764 is 46724054012.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21045042769) 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, 210752 + ... + 294119.

It is an arithmetic number, because the mean of its divisors is an integer number (1627454892).

Almost surely, 2^21045042764 is an apocalyptic number.

It is an amenable number.

21045042764 is a deficient number, since it is larger than the sum of its proper divisors (18013874644).

21045042764 is a wasteful number, since it uses less digits than its factorization.

21045042764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 505505 (or 505503 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 35.

Adding to 21045042764 its reverse (46724054012), we get a palindrome (67769096776).

The spelling of 21045042764 in words is "twenty-one billion, forty-five million, forty-two thousand, seven hundred sixty-four".