7836991661 has 2 divisors, whose sum is σ = 7836991662. Its totient is φ = 7836991660.

The previous prime is 7836991649. The next prime is 7836991709. The reversal of 7836991661 is 1661996387.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7604886436 + 232105225 = 87206^2 + 15235^2 .

It is a cyclic number.

It is not a de Polignac number, because 7836991661 - 2¹⁸ = 7836729517 is a prime.

It is a super-2 number, since 2×7836991661² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 7836991597 and 7836991606.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7836990661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3918495830 + 3918495831.

It is an arithmetic number, because the mean of its divisors is an integer number (3918495831).

Almost surely, 2^7836991661 is an apocalyptic number.

It is an amenable number.

7836991661 is a deficient number, since it is larger than the sum of its proper divisors (1).

7836991661 is an equidigital number, since it uses as much as digits as its factorization.

7836991661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2939328, while the sum is 56.

The square root of 7836991661 is about 88526.7849918882. The cubic root of 7836991661 is about 1986.3226500171.

The spelling of 7836991661 in words is "seven billion, eight hundred thirty-six million, nine hundred ninety-one thousand, six hundred sixty-one".