20500666651 has 2 divisors, whose sum is σ = 20500666652. Its totient is φ = 20500666650.

The previous prime is 20500666591. The next prime is 20500666717. The reversal of 20500666651 is 15666600502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20500666651 - 2¹⁵ = 20500633883 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20500666651.

It is not a weakly prime, because it can be changed into another prime (20500666951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10250333325 + 10250333326.

It is an arithmetic number, because the mean of its divisors is an integer number (10250333326).

Almost surely, 2^20500666651 is an apocalyptic number.

20500666651 is a deficient number, since it is larger than the sum of its proper divisors (1).

20500666651 is an equidigital number, since it uses as much as digits as its factorization.

20500666651 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64800, while the sum is 37.

The spelling of 20500666651 in words is "twenty billion, five hundred million, six hundred sixty-six thousand, six hundred fifty-one".