321663505 has 16 divisors (see below), whose sum is σ = 399848400. Its totient is φ = 248120320.

The previous prime is 321663499. The next prime is 321663509. The reversal of 321663505 is 505366123.

It can be written as a sum of positive squares in 8 ways, for example, as 17230801 + 304432704 = 4151^2 + 17448^2 .

It is not a de Polignac number, because 321663505 - 2³ = 321663497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (321663509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 186045 + ... + 187765.

It is an arithmetic number, because the mean of its divisors is an integer number (24990525).

Almost surely, 2^321663505 is an apocalyptic number.

It is an amenable number.

321663505 is a deficient number, since it is larger than the sum of its proper divisors (78184895).

321663505 is a wasteful number, since it uses less digits than its factorization.

321663505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3044.

The product of its (nonzero) digits is 16200, while the sum is 31.

The square root of 321663505 is about 17934.9799275048. The cubic root of 321663505 is about 685.1735614335.

The spelling of 321663505 in words is "three hundred twenty-one million, six hundred sixty-three thousand, five hundred five".