21605054764 has 12 divisors (see below), whose sum is σ = 37810796184. Its totient is φ = 10801970144.

The previous prime is 21605054759. The next prime is 21605054773. The reversal of 21605054764 is 46745050612.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44977 + ... + 212680.

It is an arithmetic number, because the mean of its divisors is an integer number (3150899682).

Almost surely, 2^21605054764 is an apocalyptic number.

It is an amenable number.

21605054764 is a deficient number, since it is larger than the sum of its proper divisors (16205741420).

21605054764 is a wasteful number, since it uses less digits than its factorization.

21605054764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278624 (or 278622 counting only the distinct ones).

The product of its (nonzero) digits is 201600, while the sum is 40.

The spelling of 21605054764 in words is "twenty-one billion, six hundred five million, fifty-four thousand, seven hundred sixty-four".