12666780037531 has 2 divisors, whose sum is σ = 12666780037532. Its totient is φ = 12666780037530.

The previous prime is 12666780037529. The next prime is 12666780037729. The reversal of 12666780037531 is 13573008766621.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 12666780037531 - 2¹ = 12666780037529 is a prime.

It is a super-2 number, since 2×12666780037531² (a number of 27 digits) contains 22 as substring.

Together with 12666780037529, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (12666780037231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6333390018765 + 6333390018766.

It is an arithmetic number, because the mean of its divisors is an integer number (6333390018766).

Almost surely, 2^{12666780037531} is an apocalyptic number.

12666780037531 is a deficient number, since it is larger than the sum of its proper divisors (1).

12666780037531 is an equidigital number, since it uses as much as digits as its factorization.

12666780037531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7620480, while the sum is 55.

The spelling of 12666780037531 in words is "twelve trillion, six hundred sixty-six billion, seven hundred eighty million, thirty-seven thousand, five hundred thirty-one".