21366644403 has 8 divisors (see below), whose sum is σ = 30680309968. Its totient is φ = 13148704224.

The previous prime is 21366644381. The next prime is 21366644413. The reversal of 21366644403 is 30444666312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21366644403 - 2⁸ = 21366644147 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 547862677 = 21366644403 / (2 + 1 + 3 + 6 + 6 + 6 + 4 + 4 + 4 + 0 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21366644413) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 273931300 + ... + 273931377.

It is an arithmetic number, because the mean of its divisors is an integer number (3835038746).

Almost surely, 2^21366644403 is an apocalyptic number.

21366644403 is a deficient number, since it is larger than the sum of its proper divisors (9313665565).

21366644403 is a wasteful number, since it uses less digits than its factorization.

21366644403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 547862693.

The product of its (nonzero) digits is 248832, while the sum is 39.

The spelling of 21366644403 in words is "twenty-one billion, three hundred sixty-six million, six hundred forty-four thousand, four hundred three".