321621887 has 2 divisors, whose sum is σ = 321621888. Its totient is φ = 321621886.

The previous prime is 321621863. The next prime is 321621889. The reversal of 321621887 is 788126123.

It is a strong prime.

It is an emirp because it is prime and its reverse (788126123) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 321621887 - 2⁶ = 321621823 is a prime.

It is a super-3 number, since 3×321621887³ (a number of 26 digits) contains 333 as substring.

Together with 321621889, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 321621887.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (321621889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160810943 + 160810944.

It is an arithmetic number, because the mean of its divisors is an integer number (160810944).

Almost surely, 2^321621887 is an apocalyptic number.

321621887 is a deficient number, since it is larger than the sum of its proper divisors (1).

321621887 is an equidigital number, since it uses as much as digits as its factorization.

321621887 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 38.

The square root of 321621887 is about 17933.8196433442. The cubic root of 321621887 is about 685.1440100723.

The spelling of 321621887 in words is "three hundred twenty-one million, six hundred twenty-one thousand, eight hundred eighty-seven".