664814655 has 128 divisors (see below), whose sum is σ = 1327104000. Its totient is φ = 314202240.

The previous prime is 664814641. The next prime is 664814663. The reversal of 664814655 is 556418466.

It is a Cunningham number, because it is equal to 25784²-1.

It is not a de Polignac number, because 664814655 - 2⁸ = 664814399 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

Its product of digits (691200) is a multiple of the sum of its prime divisors (300).

It is a self number, because there is not a number n which added to its sum of digits gives 664814655.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 3480610 + ... + 3480800.

It is an arithmetic number, because the mean of its divisors is an integer number (10368000).

Almost surely, 2^664814655 is an apocalyptic number.

664814655 is a deficient number, since it is larger than the sum of its proper divisors (662289345).

664814655 is a wasteful number, since it uses less digits than its factorization.

664814655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 306 (or 300 counting only the distinct ones).

The product of its digits is 691200, while the sum is 45.

The square root of 664814655 is about 25783.9999806081. Note that the first 4 decimals coincide. The cubic root of 664814655 is about 872.7707738881.

The spelling of 664814655 in words is "six hundred sixty-four million, eight hundred fourteen thousand, six hundred fifty-five".