65889242721 has 27 divisors (see below), whose sum is σ = 98860038771. Its totient is φ = 43912300608.

The previous prime is 65889242669. The next prime is 65889242723. The reversal of 65889242721 is 12724298856.

The square root of 65889242721 is 256689.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 54457356321 + 11431886400 = 233361^2 + 106920^2 .

It is a tau number, because it is divible by the number of its divisors (27).

It is not a de Polignac number, because 65889242721 - 2³⁵ = 31529504353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (65889242723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 20790225 + ... + 20793393.

Almost surely, 2^65889242721 is an apocalyptic number.

65889242721 is the 256689-th square number.

65889242721 is the 128345-th centered octagonal number.

It is an amenable number.

65889242721 is a deficient number, since it is larger than the sum of its proper divisors (32970796050).

65889242721 is an frugal number, since it uses more digits than its factorization.

65889242721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6362 (or 3172 counting only the distinct ones).

The product of its digits is 3870720, while the sum is 54.

The spelling of 65889242721 in words is "sixty-five billion, eight hundred eighty-nine million, two hundred forty-two thousand, seven hundred twenty-one".