126505897687 has 4 divisors (see below), whose sum is σ = 136237120600. Its totient is φ = 116774674776.

The previous prime is 126505897673. The next prime is 126505897691. The reversal of 126505897687 is 786798505621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 786798505621 = 31511 ⋅24969011.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-126505897687 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126505897487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4865611437 + ... + 4865611462.

It is an arithmetic number, because the mean of its divisors is an integer number (34059280150).

Almost surely, 2^126505897687 is an apocalyptic number.

126505897687 is a deficient number, since it is larger than the sum of its proper divisors (9731222913).

126505897687 is an equidigital number, since it uses as much as digits as its factorization.

126505897687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9731222912.

The product of its (nonzero) digits is 50803200, while the sum is 64.

The spelling of 126505897687 in words is "one hundred twenty-six billion, five hundred five million, eight hundred ninety-seven thousand, six hundred eighty-seven".