20644540667 has 2 divisors, whose sum is σ = 20644540668. Its totient is φ = 20644540666.

The previous prime is 20644540643. The next prime is 20644540717. The reversal of 20644540667 is 76604544602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20644540667 - 2¹² = 20644536571 is a prime.

It is not a weakly prime, because it can be changed into another prime (20644540627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10322270333 + 10322270334.

It is an arithmetic number, because the mean of its divisors is an integer number (10322270334).

Almost surely, 2^20644540667 is an apocalyptic number.

20644540667 is a deficient number, since it is larger than the sum of its proper divisors (1).

20644540667 is an equidigital number, since it uses as much as digits as its factorization.

20644540667 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 967680, while the sum is 44.

The spelling of 20644540667 in words is "twenty billion, six hundred forty-four million, five hundred forty thousand, six hundred sixty-seven".