20644662455 has 4 divisors (see below), whose sum is σ = 24773594952. Its totient is φ = 16515729960.

The previous prime is 20644662421. The next prime is 20644662461. The reversal of 20644662455 is 55426644602.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-20644662455 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 3 ways as a sum of consecutive naturals, for example, 2064466241 + ... + 2064466250.

It is an arithmetic number, because the mean of its divisors is an integer number (6193398738).

Almost surely, 2^20644662455 is an apocalyptic number.

20644662455 is a deficient number, since it is larger than the sum of its proper divisors (4128932497).

20644662455 is an equidigital number, since it uses as much as digits as its factorization.

20644662455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4128932496.

The product of its (nonzero) digits is 1382400, while the sum is 44.

The spelling of 20644662455 in words is "twenty billion, six hundred forty-four million, six hundred sixty-two thousand, four hundred fifty-five".