65001721 has 4 divisors (see below), whose sum is σ = 65260944. Its totient is φ = 64742500.

The previous prime is 65001719. The next prime is 65001743. The reversal of 65001721 is 12710056.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 65001721 - 2¹ = 65001719 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 65001692 and 65001701.

It is not an unprimeable number, because it can be changed into a prime (65001791) 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 3 ways as a sum of consecutive naturals, for example, 129235 + ... + 129736.

It is an arithmetic number, because the mean of its divisors is an integer number (16315236).

Almost surely, 2^65001721 is an apocalyptic number.

It is an amenable number.

65001721 is a deficient number, since it is larger than the sum of its proper divisors (259223).

65001721 is a wasteful number, since it uses less digits than its factorization.

65001721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259222.

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

The square root of 65001721 is about 8062.3644794812. The cubic root of 65001721 is about 402.0761243758.

Adding to 65001721 its reverse (12710056), we get a palindrome (77711777).

It can be divided in two parts, 65001 and 721, that multiplied together give a triangular number (46865721 = T₉₆₈₁).

The spelling of 65001721 in words is "sixty-five million, one thousand, seven hundred twenty-one".