9965581 has 2 divisors, whose sum is σ = 9965582. Its totient is φ = 9965580.

The previous prime is 9965573. The next prime is 9965603. The reversal of 9965581 is 1855699.

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., 8608356 + 1357225 = 2934^2 + 1165^2 .

It is a cyclic number.

It is not a de Polignac number, because 9965581 - 2³ = 9965573 is a prime.

It is a super-2 number, since 2×9965581² = 198625609335122, which contains 22 as substring.

9965581 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9965381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4982790 + 4982791.

It is an arithmetic number, because the mean of its divisors is an integer number (4982791).

Almost surely, 2^9965581 is an apocalyptic number.

It is an amenable number.

9965581 is a deficient number, since it is larger than the sum of its proper divisors (1).

9965581 is an equidigital number, since it uses as much as digits as its factorization.

9965581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 97200, while the sum is 43.

The square root of 9965581 is about 3156.8308475431. The cubic root of 9965581 is about 215.1960065800.

The spelling of 9965581 in words is "nine million, nine hundred sixty-five thousand, five hundred eighty-one".