20644216457 has 8 divisors (see below), whose sum is σ = 21414288000. Its totient is φ = 19878025104.

The previous prime is 20644216391. The next prime is 20644216459. The reversal of 20644216457 is 75461244602.

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 20644216457 - 2¹⁰ = 20644215433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20644216459) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 959207 + ... + 980492.

It is an arithmetic number, because the mean of its divisors is an integer number (2676786000).

Almost surely, 2^20644216457 is an apocalyptic number.

It is an amenable number.

20644216457 is a deficient number, since it is larger than the sum of its proper divisors (770071543).

20644216457 is a wasteful number, since it uses less digits than its factorization.

20644216457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1940095.

The product of its (nonzero) digits is 322560, while the sum is 41.

The spelling of 20644216457 in words is "twenty billion, six hundred forty-four million, two hundred sixteen thousand, four hundred fifty-seven".