40540781 has 2 divisors, whose sum is σ = 40540782. Its totient is φ = 40540780.

The previous prime is 40540757. The next prime is 40540807. The reversal of 40540781 is 18704504.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40513225 + 27556 = 6365^2 + 166^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40540781 is a prime.

It is a super-2 number, since 2×40540781² = 3287109848179922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (40540711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20270390 + 20270391.

It is an arithmetic number, because the mean of its divisors is an integer number (20270391).

Almost surely, 2^40540781 is an apocalyptic number.

It is an amenable number.

40540781 is a deficient number, since it is larger than the sum of its proper divisors (1).

40540781 is an equidigital number, since it uses as much as digits as its factorization.

40540781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 40540781 is about 6367.1642824730. The cubic root of 40540781 is about 343.5294997572.

The spelling of 40540781 in words is "forty million, five hundred forty thousand, seven hundred eighty-one".