65721001 has 2 divisors, whose sum is σ = 65721002. Its totient is φ = 65721000.

The previous prime is 65720953. The next prime is 65721049. The reversal of 65721001 is 10012756.

It is a balanced prime because it is at equal distance from previous prime (65720953) and next prime (65721049).

It can be written as a sum of positive squares in only one way, i.e., 50126400 + 15594601 = 7080^2 + 3949^2 .

It is a cyclic number.

It is not a de Polignac number, because 65721001 - 2¹³ = 65712809 is a prime.

It is not a weakly prime, because it can be changed into another prime (65721101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32860500 + 32860501.

It is an arithmetic number, because the mean of its divisors is an integer number (32860501).

Almost surely, 2^65721001 is an apocalyptic number.

It is an amenable number.

65721001 is a deficient number, since it is larger than the sum of its proper divisors (1).

65721001 is an equidigital number, since it uses as much as digits as its factorization.

65721001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 420, while the sum is 22.

The square root of 65721001 is about 8106.8490179601. The cubic root of 65721001 is about 403.5537523586.

Adding to 65721001 its reverse (10012756), we get a palindrome (75733757).

The spelling of 65721001 in words is "sixty-five million, seven hundred twenty-one thousand, one".