664232781 has 8 divisors (see below), whose sum is σ = 893921184. Its totient is φ = 438683120.

The previous prime is 664232743. The next prime is 664232783. The reversal of 664232781 is 187232466.

It is a happy number.

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 664232781 - 2²⁷ = 530015053 is a prime.

It is a super-2 number, since 2×664232781² = 882410374709987922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664232783) 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 7 ways as a sum of consecutive naturals, for example, 1034310 + ... + 1034951.

It is an arithmetic number, because the mean of its divisors is an integer number (111740148).

Almost surely, 2^664232781 is an apocalyptic number.

It is an amenable number.

664232781 is a deficient number, since it is larger than the sum of its proper divisors (229688403).

664232781 is a wasteful number, since it uses less digits than its factorization.

664232781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2069371.

The product of its digits is 96768, while the sum is 39.

The square root of 664232781 is about 25772.7138850374. The cubic root of 664232781 is about 872.5160708911.

The spelling of 664232781 in words is "six hundred sixty-four million, two hundred thirty-two thousand, seven hundred eighty-one".