387668821 has 2 divisors, whose sum is σ = 387668822. Its totient is φ = 387668820.

The previous prime is 387668819. The next prime is 387668843. The reversal of 387668821 is 128866783.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 387656721 + 12100 = 19689^2 + 110^2 .

It is a cyclic number.

It is not a de Polignac number, because 387668821 - 2¹ = 387668819 is a prime.

It is a super-2 number, since 2×387668821² = 300574229551060082, which contains 22 as substring.

Together with 387668819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (387668861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 193834410 + 193834411.

It is an arithmetic number, because the mean of its divisors is an integer number (193834411).

Almost surely, 2^387668821 is an apocalyptic number.

It is an amenable number.

387668821 is a deficient number, since it is larger than the sum of its proper divisors (1).

387668821 is an equidigital number, since it uses as much as digits as its factorization.

387668821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 774144, while the sum is 49.

The square root of 387668821 is about 19689.3072757779. The cubic root of 387668821 is about 729.1557268882.

The spelling of 387668821 in words is "three hundred eighty-seven million, six hundred sixty-eight thousand, eight hundred twenty-one".