996640081 has 2 divisors, whose sum is σ = 996640082. Its totient is φ = 996640080.

The previous prime is 996640069. The next prime is 996640087. The reversal of 996640081 is 180046699.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 710489025 + 286151056 = 26655^2 + 16916^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-996640081 is a prime.

It is a super-2 number, since 2×996640081² = 1986582902111373122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (996640087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498320040 + 498320041.

It is an arithmetic number, because the mean of its divisors is an integer number (498320041).

Almost surely, 2^996640081 is an apocalyptic number.

It is an amenable number.

996640081 is a deficient number, since it is larger than the sum of its proper divisors (1).

996640081 is an equidigital number, since it uses as much as digits as its factorization.

996640081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 996640081 is about 31569.6069186805. The cubic root of 996640081 is about 998.8787703138.

The spelling of 996640081 in words is "nine hundred ninety-six million, six hundred forty thousand, eighty-one".