40216681 has 2 divisors, whose sum is σ = 40216682. Its totient is φ = 40216680.

The previous prime is 40216637. The next prime is 40216717. The reversal of 40216681 is 18661204.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39576681 + 640000 = 6291^2 + 800^2 .

It is a cyclic number.

It is not a de Polignac number, because 40216681 - 2¹¹ = 40214633 is a prime.

It is a super-2 number, since 2×40216681² = 3234762861311522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (40216621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20108340 + 20108341.

It is an arithmetic number, because the mean of its divisors is an integer number (20108341).

Almost surely, 2^40216681 is an apocalyptic number.

It is an amenable number.

40216681 is a deficient number, since it is larger than the sum of its proper divisors (1).

40216681 is an equidigital number, since it uses as much as digits as its factorization.

40216681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 40216681 is about 6341.6623215053. The cubic root of 40216681 is about 342.6116097801.

Adding to 40216681 its reverse (18661204), we get a palindrome (58877885).

The spelling of 40216681 in words is "forty million, two hundred sixteen thousand, six hundred eighty-one".