64750721 has 16 divisors (see below), whose sum is σ = 75116160. Its totient is φ = 54672000.

The previous prime is 64750709. The next prime is 64750753. The reversal of 64750721 is 12705746.

It is a cyclic number.

It is not a de Polignac number, because 64750721 - 2⁶ = 64750657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64750771) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 240575 + ... + 240843.

It is an arithmetic number, because the mean of its divisors is an integer number (4694760).

Almost surely, 2^64750721 is an apocalyptic number.

It is an amenable number.

64750721 is a deficient number, since it is larger than the sum of its proper divisors (10365439).

64750721 is a wasteful number, since it uses less digits than its factorization.

64750721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664.

The product of its (nonzero) digits is 11760, while the sum is 32.

The square root of 64750721 is about 8046.7832703510. The cubic root of 64750721 is about 401.5579263692.

The spelling of 64750721 in words is "sixty-four million, seven hundred fifty thousand, seven hundred twenty-one".