391620101 has 2 divisors, whose sum is σ = 391620102. Its totient is φ = 391620100.

The previous prime is 391620091. The next prime is 391620157. The reversal of 391620101 is 101026193.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 377369476 + 14250625 = 19426^2 + 3775^2 .

It is an emirp because it is prime and its reverse (101026193) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 391620101 - 2⁶ = 391620037 is a prime.

It is equal to p_20913008 and since 391620101 and 20913008 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391620601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195810050 + 195810051.

It is an arithmetic number, because the mean of its divisors is an integer number (195810051).

Almost surely, 2^391620101 is an apocalyptic number.

It is an amenable number.

391620101 is a deficient number, since it is larger than the sum of its proper divisors (1).

391620101 is an equidigital number, since it uses as much as digits as its factorization.

391620101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 391620101 is about 19789.3936491243. The cubic root of 391620101 is about 731.6246427009.

Adding to 391620101 its reverse (101026193), we get a palindrome (492646294).

The spelling of 391620101 in words is "three hundred ninety-one million, six hundred twenty thousand, one hundred one".