21556056430 has 16 divisors (see below), whose sum is σ = 38803127184. Its totient is φ = 8621928000.

The previous prime is 21556056421. The next prime is 21556056437. The reversal of 21556056430 is 3465065512.

It is a self number, because there is not a number n which added to its sum of digits gives 21556056430.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21556056437) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 158689 + ... + 261331.

It is an arithmetic number, because the mean of its divisors is an integer number (2425195449).

Almost surely, 2^21556056430 is an apocalyptic number.

21556056430 is a deficient number, since it is larger than the sum of its proper divisors (17247070754).

21556056430 is a wasteful number, since it uses less digits than its factorization.

21556056430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123651.

The product of its (nonzero) digits is 108000, while the sum is 37.

The spelling of 21556056430 in words is "twenty-one billion, five hundred fifty-six million, fifty-six thousand, four hundred thirty".