391421101 has 2 divisors, whose sum is σ = 391421102. Its totient is φ = 391421100.

The previous prime is 391421053. The next prime is 391421213. The reversal of 391421101 is 101124193.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 312228900 + 79192201 = 17670^2 + 8899^2 .

It is a cyclic number.

It is not a de Polignac number, because 391421101 - 2¹³ = 391412909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391421501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195710550 + 195710551.

It is an arithmetic number, because the mean of its divisors is an integer number (195710551).

Almost surely, 2^391421101 is an apocalyptic number.

It is an amenable number.

391421101 is a deficient number, since it is larger than the sum of its proper divisors (1).

391421101 is an equidigital number, since it uses as much as digits as its factorization.

391421101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 391421101 is about 19784.3650643633. The cubic root of 391421101 is about 731.5006977762.

Adding to 391421101 its reverse (101124193), we get a palindrome (492545294).

The spelling of 391421101 in words is "three hundred ninety-one million, four hundred twenty-one thousand, one hundred one".