664738722 has 54 divisors (see below), whose sum is σ = 1479454587. Its totient is φ = 215709192.

The previous prime is 664738717. The next prime is 664738729. The reversal of 664738722 is 227837466.

It can be written as a sum of positive squares in only one way, i.e., 332369361 + 332369361 = 18231^2 + 18231^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=18231.

It is not an unprimeable number, because it can be changed into a prime (664738729) 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 26 ways as a sum of consecutive naturals, for example, 6453723 + ... + 6453825.

Almost surely, 2^664738722 is an apocalyptic number.

664738722 is an abundant number, since it is smaller than the sum of its proper divisors (814715865).

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

664738722 is a wasteful number, since it uses less digits than its factorization.

664738722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 332 (or 167 counting only the distinct ones).

The product of its digits is 677376, while the sum is 45.

The square root of 664738722 is about 25782.5274556239. The cubic root of 664738722 is about 872.7375442624.

It can be divided in two parts, 6647 and 38722, that added together give a square (45369 = 213²).

The spelling of 664738722 in words is "six hundred sixty-four million, seven hundred thirty-eight thousand, seven hundred twenty-two".