391121200021001 has 2 divisors, whose sum is σ = 391121200021002. Its totient is φ = 391121200021000.

The previous prime is 391121200020977. The next prime is 391121200021039. The reversal of 391121200021001 is 100120002121193.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 291131499755776 + 99989700265225 = 17062576^2 + 9999485^2 .

It is an emirp because it is prime and its reverse (100120002121193) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 391121200021001 - 2⁴² = 386723153509897 is a prime.

It is not a weakly prime, because it can be changed into another prime (391121200021091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195560600010500 + 195560600010501.

It is an arithmetic number, because the mean of its divisors is an integer number (195560600010501).

Almost surely, 2^{391121200021001} is an apocalyptic number.

It is an amenable number.

391121200021001 is a deficient number, since it is larger than the sum of its proper divisors (1).

391121200021001 is an equidigital number, since it uses as much as digits as its factorization.

391121200021001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 23.

Adding to 391121200021001 its reverse (100120002121193), we get a palindrome (491241202142194).

The spelling of 391121200021001 in words is "three hundred ninety-one trillion, one hundred twenty-one billion, two hundred million, twenty-one thousand, one".