65081721 has 12 divisors (see below), whose sum is σ = 88455248. Its totient is φ = 42563664.

The previous prime is 65081677. The next prime is 65081749. The reversal of 65081721 is 12718056.

65081721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 65081721 - 2⁶ = 65081657 is a prime.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65081761) 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 11 ways as a sum of consecutive naturals, for example, 4566 + ... + 12288.

Almost surely, 2^65081721 is an apocalyptic number.

It is an amenable number.

65081721 is a deficient number, since it is larger than the sum of its proper divisors (23373527).

65081721 is an equidigital number, since it uses as much as digits as its factorization.

65081721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7832 (or 7779 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 65081721 is about 8067.3242776028. The cubic root of 65081721 is about 402.2410066921.

Adding to 65081721 its reverse (12718056), we get a palindrome (77799777).

The spelling of 65081721 in words is "sixty-five million, eighty-one thousand, seven hundred twenty-one".