20644706475 has 36 divisors (see below), whose sum is σ = 37131775200. Its totient is φ = 10964412480.

The previous prime is 20644706447. The next prime is 20644706477. The reversal of 20644706475 is 57460744602.

It is not a de Polignac number, because 20644706475 - 2¹⁰ = 20644705451 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 20644706475.

It is not an unprimeable number, because it can be changed into a prime (20644706477) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 138180 + ... + 245729.

It is an arithmetic number, because the mean of its divisors is an integer number (1031438200).

Almost surely, 2^20644706475 is an apocalyptic number.

20644706475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20644706475 is a deficient number, since it is larger than the sum of its proper divisors (16487068725).

20644706475 is a wasteful number, since it uses less digits than its factorization.

20644706475 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384164 (or 384156 counting only the distinct ones).

The product of its (nonzero) digits is 1128960, while the sum is 45.

The spelling of 20644706475 in words is "twenty billion, six hundred forty-four million, seven hundred six thousand, four hundred seventy-five".