391021640417 has 2 divisors, whose sum is σ = 391021640418. Its totient is φ = 391021640416.

The previous prime is 391021640411. The next prime is 391021640497. The reversal of 391021640417 is 714046120193.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 211990259776 + 179031380641 = 460424^2 + 423121^2 .

It is a cyclic number.

It is not a de Polignac number, because 391021640417 - 2²⁴ = 391004863201 is a prime.

It is not a weakly prime, because it can be changed into another prime (391021640411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195510820208 + 195510820209.

It is an arithmetic number, because the mean of its divisors is an integer number (195510820209).

Almost surely, 2^391021640417 is an apocalyptic number.

It is an amenable number.

391021640417 is a deficient number, since it is larger than the sum of its proper divisors (1).

391021640417 is an equidigital number, since it uses as much as digits as its factorization.

391021640417 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36288, while the sum is 38.

The spelling of 391021640417 in words is "three hundred ninety-one billion, twenty-one million, six hundred forty thousand, four hundred seventeen".