40989656681 has 2 divisors, whose sum is σ = 40989656682. Its totient is φ = 40989656680.

The previous prime is 40989656651. The next prime is 40989656723. The reversal of 40989656681 is 18665698904.

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., 40989646681 + 10000 = 202459^2 + 100^2 .

It is a cyclic number.

It is not a de Polignac number, because 40989656681 - 2²² = 40985462377 is a prime.

It is a super-2 number, since 2×40989656681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (40989656651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20494828340 + 20494828341.

It is an arithmetic number, because the mean of its divisors is an integer number (20494828341).

Almost surely, 2^40989656681 is an apocalyptic number.

It is an amenable number.

40989656681 is a deficient number, since it is larger than the sum of its proper divisors (1).

40989656681 is an equidigital number, since it uses as much as digits as its factorization.

40989656681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22394880, while the sum is 62.

The spelling of 40989656681 in words is "forty billion, nine hundred eighty-nine million, six hundred fifty-six thousand, six hundred eighty-one".