64967721 has 16 divisors (see below), whose sum is σ = 106614144. Its totient is φ = 34268544.

The previous prime is 64967719. The next prime is 64967767. The reversal of 64967721 is 12776946.

It is not a de Polignac number, because 64967721 - 2¹ = 64967719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64967701) 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, 118716 + ... + 119261.

It is an arithmetic number, because the mean of its divisors is an integer number (6663384).

Almost surely, 2^64967721 is an apocalyptic number.

It is an amenable number.

64967721 is a deficient number, since it is larger than the sum of its proper divisors (41646423).

64967721 is a wasteful number, since it uses less digits than its factorization.

64967721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238000.

The product of its digits is 127008, while the sum is 42.

The square root of 64967721 is about 8060.2556411072. The cubic root of 64967721 is about 402.0060084248.

The spelling of 64967721 in words is "sixty-four million, nine hundred sixty-seven thousand, seven hundred twenty-one".