20865777671 has 2 divisors, whose sum is σ = 20865777672. Its totient is φ = 20865777670.

The previous prime is 20865777659. The next prime is 20865777697. The reversal of 20865777671 is 17677756802.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20865777671 - 2¹⁸ = 20865515527 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20865777871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10432888835 + 10432888836.

It is an arithmetic number, because the mean of its divisors is an integer number (10432888836).

Almost surely, 2^20865777671 is an apocalyptic number.

20865777671 is a deficient number, since it is larger than the sum of its proper divisors (1).

20865777671 is an equidigital number, since it uses as much as digits as its factorization.

20865777671 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6914880, while the sum is 56.

The spelling of 20865777671 in words is "twenty billion, eight hundred sixty-five million, seven hundred seventy-seven thousand, six hundred seventy-one".