81965417 has 4 divisors (see below), whose sum is σ = 82010436. Its totient is φ = 81920400.

The previous prime is 81965407. The next prime is 81965431. The reversal of 81965417 is 71456918.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19175641 + 62789776 = 4379^2 + 7924^2 .

It is a cyclic number.

It is not a de Polignac number, because 81965417 - 2¹⁸ = 81703273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81965407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19658 + ... + 23459.

It is an arithmetic number, because the mean of its divisors is an integer number (20502609).

Almost surely, 2^81965417 is an apocalyptic number.

It is an amenable number.

81965417 is a deficient number, since it is larger than the sum of its proper divisors (45019).

81965417 is a wasteful number, since it uses less digits than its factorization.

81965417 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45018.

The product of its digits is 60480, while the sum is 41.

The square root of 81965417 is about 9053.4754100290. The cubic root of 81965417 is about 434.3870647029.

The spelling of 81965417 in words is "eighty-one million, nine hundred sixty-five thousand, four hundred seventeen".