664635426 has 48 divisors (see below), whose sum is σ = 1645032384. Its totient is φ = 175286592.

The previous prime is 664635421. The next prime is 664635437. The reversal of 664635426 is 624536466.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664635421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 39721 + ... + 53916.

It is an arithmetic number, because the mean of its divisors is an integer number (34271508).

Almost surely, 2^664635426 is an apocalyptic number.

664635426 is an abundant number, since it is smaller than the sum of its proper divisors (980396958).

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

664635426 is a wasteful number, since it uses less digits than its factorization.

664635426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93675 (or 93662 counting only the distinct ones).

The product of its digits is 622080, while the sum is 42.

The square root of 664635426 is about 25780.5241606915. The cubic root of 664635426 is about 872.6923360403.

The spelling of 664635426 in words is "six hundred sixty-four million, six hundred thirty-five thousand, four hundred twenty-six".