21043687384 has 16 divisors (see below), whose sum is σ = 39481041600. Its totient is φ = 10515409632.

The previous prime is 21043687333. The next prime is 21043687387. The reversal of 21043687384 is 48378634012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21043687387) 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 3 ways as a sum of consecutive naturals, for example, 790344 + ... + 816535.

It is an arithmetic number, because the mean of its divisors is an integer number (2467565100).

Almost surely, 2^21043687384 is an apocalyptic number.

It is an amenable number.

21043687384 is a deficient number, since it is larger than the sum of its proper divisors (18437354216).

21043687384 is a wasteful number, since it uses less digits than its factorization.

21043687384 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1608522 (or 1608518 counting only the distinct ones).

The product of its (nonzero) digits is 774144, while the sum is 46.

The spelling of 21043687384 in words is "twenty-one billion, forty-three million, six hundred eighty-seven thousand, three hundred eighty-four".