21045123564 has 48 divisors (see below), whose sum is σ = 51291851520. Its totient is φ = 6707373120.

The previous prime is 21045123553. The next prime is 21045123601. The reversal of 21045123564 is 46532154012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 257722 + ... + 329409.

It is an arithmetic number, because the mean of its divisors is an integer number (1068580240).

Almost surely, 2^21045123564 is an apocalyptic number.

It is an amenable number.

21045123564 is an abundant number, since it is smaller than the sum of its proper divisors (30246727956).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21045123564 is a wasteful number, since it uses less digits than its factorization.

21045123564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 587270 (or 587268 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 33.

Adding to 21045123564 its reverse (46532154012), we get a palindrome (67577277576).

The spelling of 21045123564 in words is "twenty-one billion, forty-five million, one hundred twenty-three thousand, five hundred sixty-four".