21663540056145 has 64 divisors (see below), whose sum is σ = 37392674215680. Its totient is φ = 10646648881152.

The previous prime is 21663540056129. The next prime is 21663540056161. The reversal of 21663540056145 is 54165004536612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21663540056129) and next prime (21663540056161).

It is not a de Polignac number, because 21663540056145 - 2⁴ = 21663540056129 is a prime.

It is a super-3 number, since 3×21663540056145³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a junction number, because it is equal to n+sod(n) for n = 21663540056094 and 21663540056103.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 281295214 + ... + 281372216.

It is an arithmetic number, because the mean of its divisors is an integer number (584260534620).

Almost surely, 2^{21663540056145} is an apocalyptic number.

It is an amenable number.

21663540056145 is a deficient number, since it is larger than the sum of its proper divisors (15729134159535).

21663540056145 is a wasteful number, since it uses less digits than its factorization.

21663540056145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79506.

The product of its (nonzero) digits is 2592000, while the sum is 48.

The spelling of 21663540056145 in words is "twenty-one trillion, six hundred sixty-three billion, five hundred forty million, fifty-six thousand, one hundred forty-five".