321138021 has 8 divisors (see below), whose sum is σ = 441996544. Its totient is φ = 207185760.

The previous prime is 321138017. The next prime is 321138031. The reversal of 321138021 is 120831123.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 321138021 - 2² = 321138017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (321138031) 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 7 ways as a sum of consecutive naturals, for example, 1726456 + ... + 1726641.

It is an arithmetic number, because the mean of its divisors is an integer number (55249568).

Almost surely, 2^321138021 is an apocalyptic number.

321138021 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

321138021 is a deficient number, since it is larger than the sum of its proper divisors (120858523).

321138021 is a wasteful number, since it uses less digits than its factorization.

321138021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3453131.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 321138021 is about 17920.3242437184. The cubic root of 321138021 is about 684.8002479348.

Adding to 321138021 its reverse (120831123), we get a palindrome (441969144).

The spelling of 321138021 in words is "three hundred twenty-one million, one hundred thirty-eight thousand, twenty-one".