20661266455 has 8 divisors (see below), whose sum is σ = 26251962192. Its totient is φ = 15556718208.

The previous prime is 20661266419. The next prime is 20661266471. The reversal of 20661266455 is 55466216602.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 20661266455 - 2²¹ = 20659169303 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121536777 + ... + 121536946.

It is an arithmetic number, because the mean of its divisors is an integer number (3281495274).

Almost surely, 2^20661266455 is an apocalyptic number.

20661266455 is a deficient number, since it is larger than the sum of its proper divisors (5590695737).

20661266455 is a wasteful number, since it uses less digits than its factorization.

20661266455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243073745.

The product of its (nonzero) digits is 518400, while the sum is 43.

The spelling of 20661266455 in words is "twenty billion, six hundred sixty-one million, two hundred sixty-six thousand, four hundred fifty-five".