9943249681 has 2 divisors, whose sum is σ = 9943249682. Its totient is φ = 9943249680.

The previous prime is 9943249643. The next prime is 9943249711. The reversal of 9943249681 is 1869423499.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6354640656 + 3588609025 = 79716^2 + 59905^2 .

It is a cyclic number.

It is not a de Polignac number, because 9943249681 - 2¹³ = 9943241489 is a prime.

It is a super-2 number, since 2×9943249681² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (9943249621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4971624840 + 4971624841.

It is an arithmetic number, because the mean of its divisors is an integer number (4971624841).

Almost surely, 2^9943249681 is an apocalyptic number.

It is an amenable number.

9943249681 is a deficient number, since it is larger than the sum of its proper divisors (1).

9943249681 is an equidigital number, since it uses as much as digits as its factorization.

9943249681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3359232, while the sum is 55.

The square root of 9943249681 is about 99715.8446837813. The cubic root of 9943249681 is about 2150.3514609138.

The spelling of 9943249681 in words is "nine billion, nine hundred forty-three million, two hundred forty-nine thousand, six hundred eighty-one".