664273261 has 4 divisors (see below), whose sum is σ = 665326624. Its totient is φ = 663219900.

The previous prime is 664273243. The next prime is 664273273. The reversal of 664273261 is 162372466.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 162372466 = 2 ⋅81186233.

It is a cyclic number.

It is not a de Polignac number, because 664273261 - 2¹¹ = 664271213 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 664273261.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664273201) 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 3 ways as a sum of consecutive naturals, for example, 525735 + ... + 526996.

It is an arithmetic number, because the mean of its divisors is an integer number (166331656).

Almost surely, 2^664273261 is an apocalyptic number.

It is an amenable number.

664273261 is a deficient number, since it is larger than the sum of its proper divisors (1053363).

664273261 is a wasteful number, since it uses less digits than its factorization.

664273261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1053362.

The product of its digits is 72576, while the sum is 37.

The square root of 664273261 is about 25773.4991997594. The cubic root of 664273261 is about 872.5337949652.

The spelling of 664273261 in words is "six hundred sixty-four million, two hundred seventy-three thousand, two hundred sixty-one".