391021201 has 4 divisors (see below), whose sum is σ = 391374900. Its totient is φ = 390667504.

The previous prime is 391021187. The next prime is 391021207. The reversal of 391021201 is 102120193.

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

It can be written as a sum of positive squares in 2 ways, for example, as 176252176 + 214769025 = 13276^2 + 14655^2 .

It is a cyclic number.

It is not a de Polignac number, because 391021201 - 2¹³ = 391013009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391021207) 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 3 ways as a sum of consecutive naturals, for example, 175186 + ... + 177403.

It is an arithmetic number, because the mean of its divisors is an integer number (97843725).

Almost surely, 2^391021201 is an apocalyptic number.

It is an amenable number.

391021201 is a deficient number, since it is larger than the sum of its proper divisors (353699).

391021201 is a wasteful number, since it uses less digits than its factorization.

391021201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 353698.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 391021201 is about 19774.2560163461. The cubic root of 391021201 is about 731.2514974426.

Adding to 391021201 its reverse (102120193), we get a palindrome (493141394).

The spelling of 391021201 in words is "three hundred ninety-one million, twenty-one thousand, two hundred one".