866786517537431 has 2 divisors, whose sum is σ = 866786517537432. Its totient is φ = 866786517537430.

The previous prime is 866786517537407. The next prime is 866786517537509. The reversal of 866786517537431 is 134735715687668.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-866786517537431 is a prime.

It is a super-2 number, since 2×866786517537431² (a number of 31 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866786517557431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433393258768715 + 433393258768716.

It is an arithmetic number, because the mean of its divisors is an integer number (433393258768716).

Almost surely, 2^{866786517537431} is an apocalyptic number.

866786517537431 is a deficient number, since it is larger than the sum of its proper divisors (1).

866786517537431 is an equidigital number, since it uses as much as digits as its factorization.

866786517537431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4267468800, while the sum is 77.

The spelling of 866786517537431 in words is "eight hundred sixty-six trillion, seven hundred eighty-six billion, five hundred seventeen million, five hundred thirty-seven thousand, four hundred thirty-one".