21493932728 has 32 divisors (see below), whose sum is σ = 42927343200. Its totient is φ = 10054213632.

The previous prime is 21493932673. The next prime is 21493932731. The reversal of 21493932728 is 82723939412.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 450473 + ... + 495896.

It is an arithmetic number, because the mean of its divisors is an integer number (1341479475).

Almost surely, 2^21493932728 is an apocalyptic number.

It is an amenable number.

21493932728 is a deficient number, since it is larger than the sum of its proper divisors (21433410472).

21493932728 is a wasteful number, since it uses less digits than its factorization.

21493932728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 946559 (or 946555 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 50.

The spelling of 21493932728 in words is "twenty-one billion, four hundred ninety-three million, nine hundred thirty-two thousand, seven hundred twenty-eight".