65816621 has 8 divisors (see below), whose sum is σ = 72042264. Its totient is φ = 59757120.

The previous prime is 65816609. The next prime is 65816623. The reversal of 65816621 is 12661856.

It is a happy number.

65816621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 44521 + 65772100 = 211^2 + 8110^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 65816621 - 2⁶ = 65816557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65816623) 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 7 ways as a sum of consecutive naturals, for example, 40706 + ... + 42291.

It is an arithmetic number, because the mean of its divisors is an integer number (9005283).

Almost surely, 2^65816621 is an apocalyptic number.

65816621 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

65816621 is a deficient number, since it is larger than the sum of its proper divisors (6225643).

65816621 is a wasteful number, since it uses less digits than its factorization.

65816621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83071.

The product of its digits is 17280, while the sum is 35.

The square root of 65816621 is about 8112.7443568746. The cubic root of 65816621 is about 403.7493727845.

The spelling of 65816621 in words is "sixty-five million, eight hundred sixteen thousand, six hundred twenty-one".