664631344381 has 8 divisors (see below), whose sum is σ = 668106561528. Its totient is φ = 661164000000.

The previous prime is 664631344309. The next prime is 664631344441. The reversal of 664631344381 is 183443136466.

It can be written as a sum of positive squares in 4 ways, for example, as 391489227481 + 273142116900 = 625691^2 + 522630^2 .

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 664631344381 - 2⁷ = 664631344253 is a prime.

It is a super-2 number, since 2×664631344381² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664631344681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1798870 + ... + 2136631.

It is an arithmetic number, because the mean of its divisors is an integer number (83513320191).

Almost surely, 2^664631344381 is an apocalyptic number.

It is an amenable number.

664631344381 is a deficient number, since it is larger than the sum of its proper divisors (3475217147).

664631344381 is a wasteful number, since it uses less digits than its factorization.

664631344381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3936383.

The product of its digits is 2985984, while the sum is 49.

The spelling of 664631344381 in words is "six hundred sixty-four billion, six hundred thirty-one million, three hundred forty-four thousand, three hundred eighty-one".