65868721 has 4 divisors (see below), whose sum is σ = 66985200. Its totient is φ = 64752244.

The previous prime is 65868701. The next prime is 65868731. The reversal of 65868721 is 12786856.

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 65868721 - 2¹⁵ = 65835953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65868701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 558151 + ... + 558268.

It is an arithmetic number, because the mean of its divisors is an integer number (16746300).

Almost surely, 2^65868721 is an apocalyptic number.

It is an amenable number.

65868721 is a deficient number, since it is larger than the sum of its proper divisors (1116479).

65868721 is a wasteful number, since it uses less digits than its factorization.

65868721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1116478.

The product of its digits is 161280, while the sum is 43.

The square root of 65868721 is about 8115.9547189471. The cubic root of 65868721 is about 403.8558797932.

The spelling of 65868721 in words is "sixty-five million, eight hundred sixty-eight thousand, seven hundred twenty-one".