640765481 has 8 divisors (see below), whose sum is σ = 675225600. Its totient is φ = 606378960.

The previous prime is 640765451. The next prime is 640765529. The reversal of 640765481 is 184567046.

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 640765481 - 2⁶ = 640765417 is a prime.

It is a super-2 number, since 2×640765481² = 821160803282322722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640765451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41 + ... + 35798.

It is an arithmetic number, because the mean of its divisors is an integer number (84403200).

Almost surely, 2^640765481 is an apocalyptic number.

It is an amenable number.

640765481 is a deficient number, since it is larger than the sum of its proper divisors (34460119).

640765481 is a wasteful number, since it uses less digits than its factorization.

640765481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36799.

The product of its (nonzero) digits is 161280, while the sum is 41.

The square root of 640765481 is about 25313.3459068532. The cubic root of 640765481 is about 862.1173180439.

The spelling of 640765481 in words is "six hundred forty million, seven hundred sixty-five thousand, four hundred eighty-one".