20644274317440 has 128 divisors (see below), whose sum is σ = 65903482180800. Its totient is φ = 5496785702912.

The previous prime is 20644274317409. The next prime is 20644274317441. The reversal of 20644274317440 is 4471347244602.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 20644274317440.

It is not an unprimeable number, because it can be changed into a prime (20644274317441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6892707 + ... + 9423266.

Almost surely, 2^{20644274317440} is an apocalyptic number.

20644274317440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20644274317440 is an abundant number, since it is smaller than the sum of its proper divisors (45259207863360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20644274317440 is a wasteful number, since it uses less digits than its factorization.

20644274317440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16316654 (or 16316642 counting only the distinct ones).

The product of its (nonzero) digits is 3612672, while the sum is 48.

The spelling of 20644274317440 in words is "twenty trillion, six hundred forty-four billion, two hundred seventy-four million, three hundred seventeen thousand, four hundred forty".