40208578011781 has 2 divisors, whose sum is σ = 40208578011782. Its totient is φ = 40208578011780.

The previous prime is 40208578011779. The next prime is 40208578011863. The reversal of 40208578011781 is 18711087580204.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39970326639681 + 238251372100 = 6322209^2 + 488110^2 .

It is a cyclic number.

It is not a de Polignac number, because 40208578011781 - 2¹ = 40208578011779 is a prime.

It is a super-2 number, since 2×40208578011781² (a number of 28 digits) contains 22 as substring.

Together with 40208578011779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40208578012781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20104289005890 + 20104289005891.

It is an arithmetic number, because the mean of its divisors is an integer number (20104289005891).

Almost surely, 2^{40208578011781} is an apocalyptic number.

It is an amenable number.

40208578011781 is a deficient number, since it is larger than the sum of its proper divisors (1).

40208578011781 is an equidigital number, since it uses as much as digits as its factorization.

40208578011781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1003520, while the sum is 52.

The spelling of 40208578011781 in words is "forty trillion, two hundred eight billion, five hundred seventy-eight million, eleven thousand, seven hundred eighty-one".