64448780721 has 32 divisors (see below), whose sum is σ = 98067957120. Its totient is φ = 37359168000.

The previous prime is 64448780719. The next prime is 64448780749. The reversal of 64448780721 is 12708784446.

It is not a de Polignac number, because 64448780721 - 2¹ = 64448780719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64448780701) 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 31 ways as a sum of consecutive naturals, for example, 648555 + ... + 741296.

It is an arithmetic number, because the mean of its divisors is an integer number (3064623660).

Almost surely, 2^64448780721 is an apocalyptic number.

It is an amenable number.

64448780721 is a deficient number, since it is larger than the sum of its proper divisors (33619176399).

64448780721 is a wasteful number, since it uses less digits than its factorization.

64448780721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1389937.

The product of its (nonzero) digits is 2408448, while the sum is 51.

The spelling of 64448780721 in words is "sixty-four billion, four hundred forty-eight million, seven hundred eighty thousand, seven hundred twenty-one".