208021001 has 4 divisors (see below), whose sum is σ = 208638612. Its totient is φ = 207403392.

The previous prime is 208020979. The next prime is 208021007. The reversal of 208021001 is 100120802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 100120802 = 2 ⋅50060401.

It can be written as a sum of positive squares in 2 ways, for example, as 16613776 + 191407225 = 4076^2 + 13835^2 .

It is a cyclic number.

It is not a de Polignac number, because 208021001 - 2¹⁸ = 207758857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (208021007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 308300 + ... + 308973.

It is an arithmetic number, because the mean of its divisors is an integer number (52159653).

Almost surely, 2^208021001 is an apocalyptic number.

It is an amenable number.

208021001 is a deficient number, since it is larger than the sum of its proper divisors (617611).

208021001 is an equidigital number, since it uses as much as digits as its factorization.

208021001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 617610.

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 208021001 is about 14422.9331621553. The cubic root of 208021001 is about 592.5191538373.

Adding to 208021001 its reverse (100120802), we get a palindrome (308141803).

It can be divided in two parts, 20802 and 1001, that multiplied together give a palindrome (20822802).

The spelling of 208021001 in words is "two hundred eight million, twenty-one thousand, one".