64720613 has 4 divisors (see below), whose sum is σ = 64830348. Its totient is φ = 64610880.

The previous prime is 64720609. The next prime is 64720619. The reversal of 64720613 is 31602746.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 53684929 + 11035684 = 7327^2 + 3322^2 .

It is a cyclic number.

It is not a de Polignac number, because 64720613 - 2² = 64720609 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64720619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53978 + ... + 55163.

It is an arithmetic number, because the mean of its divisors is an integer number (16207587).

Almost surely, 2^64720613 is an apocalyptic number.

It is an amenable number.

64720613 is a deficient number, since it is larger than the sum of its proper divisors (109735).

64720613 is a wasteful number, since it uses less digits than its factorization.

64720613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109734.

The product of its (nonzero) digits is 6048, while the sum is 29.

The square root of 64720613 is about 8044.9122431509. The cubic root of 64720613 is about 401.4956774848.

The spelling of 64720613 in words is "sixty-four million, seven hundred twenty thousand, six hundred thirteen".