40689031681 has 2 divisors, whose sum is σ = 40689031682. Its totient is φ = 40689031680.

The previous prime is 40689031657. The next prime is 40689031717. The reversal of 40689031681 is 18613098604.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40475404225 + 213627456 = 201185^2 + 14616^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-40689031681 is a prime.

It is a super-2 number, since 2×40689031681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (40689031631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20344515840 + 20344515841.

It is an arithmetic number, because the mean of its divisors is an integer number (20344515841).

Almost surely, 2^40689031681 is an apocalyptic number.

It is an amenable number.

40689031681 is a deficient number, since it is larger than the sum of its proper divisors (1).

40689031681 is an equidigital number, since it uses as much as digits as its factorization.

40689031681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 248832, while the sum is 46.

The spelling of 40689031681 in words is "forty billion, six hundred eighty-nine million, thirty-one thousand, six hundred eighty-one".