387831321 has 20 divisors (see below), whose sum is σ = 579886692. Its totient is φ = 258316128.

The previous prime is 387831307. The next prime is 387831329. The reversal of 387831321 is 123138783.

It can be written as a sum of positive squares in 2 ways, for example, as 229977225 + 157854096 = 15165^2 + 12564^2 .

It is not a de Polignac number, because 387831321 - 2⁵ = 387831289 is a prime.

It is not an unprimeable number, because it can be changed into a prime (387831329) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 155335 + ... + 157811.

Almost surely, 2^387831321 is an apocalyptic number.

It is an amenable number.

387831321 is a deficient number, since it is larger than the sum of its proper divisors (192055371).

387831321 is a wasteful number, since it uses less digits than its factorization.

387831321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4422 (or 4413 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 387831321 is about 19693.4334487412. The cubic root of 387831321 is about 729.2575932644.

It can be divided in two parts, 38783 and 1321, that added together give a palindrome (40104).

The spelling of 387831321 in words is "three hundred eighty-seven million, eight hundred thirty-one thousand, three hundred twenty-one".