664234421 has 6 divisors (see below), whose sum is σ = 705605730. Its totient is φ = 625161536.

The previous prime is 664234393. The next prime is 664234451. The reversal of 664234421 is 124432466.

It can be written as a sum of positive squares in 3 ways, for example, as 99221521 + 565012900 = 9961^2 + 23770^2 .

It is not a de Polignac number, because 664234421 - 2¹⁰ = 664233397 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664234451) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1148906 + ... + 1149483.

It is an arithmetic number, because the mean of its divisors is an integer number (117600955).

Almost surely, 2^664234421 is an apocalyptic number.

It is an amenable number.

664234421 is a deficient number, since it is larger than the sum of its proper divisors (41371309).

664234421 is a wasteful number, since it uses less digits than its factorization.

664234421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2298423 (or 2298406 counting only the distinct ones).

The product of its digits is 27648, while the sum is 32.

The square root of 664234421 is about 25772.7457016128. The cubic root of 664234421 is about 872.5167889753.

Adding to 664234421 its reverse (124432466), we get a palindrome (788666887).

The spelling of 664234421 in words is "six hundred sixty-four million, two hundred thirty-four thousand, four hundred twenty-one".