321928987 has 4 divisors (see below), whose sum is σ = 322195600. Its totient is φ = 321662376.

The previous prime is 321928973. The next prime is 321929059. The reversal of 321928987 is 789829123.

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

It is a cyclic number.

It is not a de Polignac number, because 321928987 - 2²³ = 313540379 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 321928987.

It is not an unprimeable number, because it can be changed into a prime (321928687) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131487 + ... + 133912.

It is an arithmetic number, because the mean of its divisors is an integer number (80548900).

Almost surely, 2^321928987 is an apocalyptic number.

321928987 is a deficient number, since it is larger than the sum of its proper divisors (266613).

321928987 is a wasteful number, since it uses less digits than its factorization.

321928987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266612.

The product of its digits is 435456, while the sum is 49.

The square root of 321928987 is about 17942.3796359346. The cubic root of 321928987 is about 685.3620101529.

The spelling of 321928987 in words is "three hundred twenty-one million, nine hundred twenty-eight thousand, nine hundred eighty-seven".