21055646003 has 4 divisors (see below), whose sum is σ = 24063595440. Its totient is φ = 18047696568.

The previous prime is 21055645999. The next prime is 21055646009. The reversal of 21055646003 is 30064655012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21055646003 - 2² = 21055645999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21055646009) 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 3 ways as a sum of consecutive naturals, for example, 1503974708 + ... + 1503974721.

It is an arithmetic number, because the mean of its divisors is an integer number (6015898860).

Almost surely, 2^21055646003 is an apocalyptic number.

21055646003 is a deficient number, since it is larger than the sum of its proper divisors (3007949437).

21055646003 is an equidigital number, since it uses as much as digits as its factorization.

21055646003 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3007949436.

The product of its (nonzero) digits is 21600, while the sum is 32.

Subtracting 21055646003 from its reverse (30064655012), we obtain a palindrome (9009009009).

The spelling of 21055646003 in words is "twenty-one billion, fifty-five million, six hundred forty-six thousand, three".