21263666165603 has 16 divisors (see below), whose sum is σ = 21500505062400. Its totient is φ = 21028150994400.

The previous prime is 21263666165597. The next prime is 21263666165611. The reversal of 21263666165603 is 30656166636212.

It is a cyclic number.

It is not a de Polignac number, because 21263666165603 - 2³⁴ = 21246486296419 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21263666155603) 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, 459622493 + ... + 459668753.

It is an arithmetic number, because the mean of its divisors is an integer number (1343781566400).

Almost surely, 2^{21263666165603} is an apocalyptic number.

21263666165603 is a deficient number, since it is larger than the sum of its proper divisors (236838896797).

21263666165603 is a wasteful number, since it uses less digits than its factorization.

21263666165603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60458.

The product of its (nonzero) digits is 8398080, while the sum is 53.

The spelling of 21263666165603 in words is "twenty-one trillion, two hundred sixty-three billion, six hundred sixty-six million, one hundred sixty-five thousand, six hundred three".