40011781 has 2 divisors, whose sum is σ = 40011782. Its totient is φ = 40011780.

The previous prime is 40011757. The next prime is 40011823. The reversal of 40011781 is 18711004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 33930625 + 6081156 = 5825^2 + 2466^2 .

It is a cyclic number.

It is not a de Polignac number, because 40011781 - 2⁵ = 40011749 is a prime.

It is a super-2 number, since 2×40011781² = 3201885237583922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40011281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20005890 + 20005891.

It is an arithmetic number, because the mean of its divisors is an integer number (20005891).

Almost surely, 2^40011781 is an apocalyptic number.

It is an amenable number.

40011781 is a deficient number, since it is larger than the sum of its proper divisors (1).

40011781 is an equidigital number, since it uses as much as digits as its factorization.

40011781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 40011781 is about 6325.4866215968. The cubic root of 40011781 is about 342.0287614173.

Adding to 40011781 its reverse (18711004), we get a palindrome (58722785).

The spelling of 40011781 in words is "forty million, eleven thousand, seven hundred eighty-one".