664221455 has 4 divisors (see below), whose sum is σ = 797065752. Its totient is φ = 531377160.

The previous prime is 664221403. The next prime is 664221463. The reversal of 664221455 is 554122466.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 664221455 - 2¹⁸ = 663959311 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66422141 + ... + 66422150.

It is an arithmetic number, because the mean of its divisors is an integer number (199266438).

Almost surely, 2^664221455 is an apocalyptic number.

664221455 is a deficient number, since it is larger than the sum of its proper divisors (132844297).

664221455 is a wasteful number, since it uses less digits than its factorization.

664221455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132844296.

The product of its digits is 57600, while the sum is 35.

The square root of 664221455 is about 25772.4941555915. The cubic root of 664221455 is about 872.5111116994.

The spelling of 664221455 in words is "six hundred sixty-four million, two hundred twenty-one thousand, four hundred fifty-five".