64660689405 has 96 divisors (see below), whose sum is σ = 132207435360. Its totient is φ = 28927180800.

The previous prime is 64660689397. The next prime is 64660689407. The reversal of 64660689405 is 50498606646.

It can be written as a sum of positive squares in 16 ways, for example, as 36394337529 + 28266351876 = 190773^2 + 168126^2 .

It is not a de Polignac number, because 64660689405 - 2³ = 64660689397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64660689407) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 176305 + ... + 400505.

It is an arithmetic number, because the mean of its divisors is an integer number (1377160785).

Almost surely, 2^64660689405 is an apocalyptic number.

64660689405 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

64660689405 is an abundant number, since it is smaller than the sum of its proper divisors (67546745955).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

64660689405 is a wasteful number, since it uses less digits than its factorization.

64660689405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224271 (or 224268 counting only the distinct ones).

The product of its (nonzero) digits is 7464960, while the sum is 54.

The spelling of 64660689405 in words is "sixty-four billion, six hundred sixty million, six hundred eighty-nine thousand, four hundred five".