20640681179 has 4 divisors (see below), whose sum is σ = 21727032840. Its totient is φ = 19554329520.

The previous prime is 20640681133. The next prime is 20640681181. The reversal of 20640681179 is 97118604602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97118604602 = 2 ⋅48559302301.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20640681179 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20640681109) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 543175802 + ... + 543175839.

It is an arithmetic number, because the mean of its divisors is an integer number (5431758210).

Almost surely, 2^20640681179 is an apocalyptic number.

20640681179 is a deficient number, since it is larger than the sum of its proper divisors (1086351661).

20640681179 is a wasteful number, since it uses less digits than its factorization.

20640681179 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1086351660.

The product of its (nonzero) digits is 145152, while the sum is 44.

The spelling of 20640681179 in words is "twenty billion, six hundred forty million, six hundred eighty-one thousand, one hundred seventy-nine".