20665657427 has 2 divisors, whose sum is σ = 20665657428. Its totient is φ = 20665657426.

The previous prime is 20665657319. The next prime is 20665657429. The reversal of 20665657427 is 72475656602.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20665657427 - 2⁸ = 20665657171 is a prime.

Together with 20665657429, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20665657429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10332828713 + 10332828714.

It is an arithmetic number, because the mean of its divisors is an integer number (10332828714).

Almost surely, 2^20665657427 is an apocalyptic number.

20665657427 is a deficient number, since it is larger than the sum of its proper divisors (1).

20665657427 is an equidigital number, since it uses as much as digits as its factorization.

20665657427 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4233600, while the sum is 50.

The spelling of 20665657427 in words is "twenty billion, six hundred sixty-five million, six hundred fifty-seven thousand, four hundred twenty-seven".