65721169 has 2 divisors, whose sum is σ = 65721170. Its totient is φ = 65721168.

The previous prime is 65721121. The next prime is 65721179. The reversal of 65721169 is 96112756.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57380625 + 8340544 = 7575^2 + 2888^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65721169 is a prime.

It is a super-4 number, since 4×65721169⁴ (a number of 32 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (65721119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32860584 + 32860585.

It is an arithmetic number, because the mean of its divisors is an integer number (32860585).

Almost surely, 2^65721169 is an apocalyptic number.

It is an amenable number.

65721169 is a deficient number, since it is larger than the sum of its proper divisors (1).

65721169 is an equidigital number, since it uses as much as digits as its factorization.

65721169 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 37.

The square root of 65721169 is about 8106.8593795625. The cubic root of 65721169 is about 403.5540962211.

It can be divided in two parts, 6572116 and 9, that added together give a triangular number (6572125 = T₃₆₂₅).

The spelling of 65721169 in words is "sixty-five million, seven hundred twenty-one thousand, one hundred sixty-nine".