21644106503451 has 16 divisors (see below), whose sum is σ = 29970103226400. Its totient is φ = 13877629165568.

The previous prime is 21644106503423. The next prime is 21644106503471. The reversal of 21644106503451 is 15430560144612.

It is a cyclic number.

It is not a de Polignac number, because 21644106503451 - 2³⁴ = 21626926634267 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21644106503471) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 483990936 + ... + 484035653.

It is an arithmetic number, because the mean of its divisors is an integer number (1873131451650).

Almost surely, 2^{21644106503451} is an apocalyptic number.

21644106503451 is a deficient number, since it is larger than the sum of its proper divisors (8325996722949).

21644106503451 is a wasteful number, since it uses less digits than its factorization.

21644106503451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 968026878.

The product of its (nonzero) digits is 345600, while the sum is 42.

The spelling of 21644106503451 in words is "twenty-one trillion, six hundred forty-four billion, one hundred six million, five hundred three thousand, four hundred fifty-one".