21357533978663 has 2 divisors, whose sum is σ = 21357533978664. Its totient is φ = 21357533978662.

The previous prime is 21357533978633. The next prime is 21357533978707. The reversal of 21357533978663 is 36687933575312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21357533978663 - 2²⁰ = 21357532930087 is a prime.

It is a super-2 number, since 2×21357533978663² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21357533978593 and 21357533978602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21357533978633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10678766989331 + 10678766989332.

It is an arithmetic number, because the mean of its divisors is an integer number (10678766989332).

Almost surely, 2^{21357533978663} is an apocalyptic number.

21357533978663 is a deficient number, since it is larger than the sum of its proper divisors (1).

21357533978663 is an equidigital number, since it uses as much as digits as its factorization.

21357533978663 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 514382400, while the sum is 68.

The spelling of 21357533978663 in words is "twenty-one trillion, three hundred fifty-seven billion, five hundred thirty-three million, nine hundred seventy-eight thousand, six hundred sixty-three".