64716721 has 8 divisors (see below), whose sum is σ = 65894400. Its totient is φ = 63548160.

The previous prime is 64716709. The next prime is 64716749. The reversal of 64716721 is 12761746.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 64716721 - 2⁹ = 64716209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64716761) 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 7 ways as a sum of consecutive naturals, for example, 12945 + ... + 17233.

It is an arithmetic number, because the mean of its divisors is an integer number (8236800).

Almost surely, 2^64716721 is an apocalyptic number.

It is an amenable number.

64716721 is a deficient number, since it is larger than the sum of its proper divisors (1177679).

64716721 is a wasteful number, since it uses less digits than its factorization.

64716721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4559.

The product of its digits is 14112, while the sum is 34.

The square root of 64716721 is about 8044.6703475034. The cubic root of 64716721 is about 401.4876292890.

The spelling of 64716721 in words is "sixty-four million, seven hundred sixteen thousand, seven hundred twenty-one".