391917601 has 2 divisors, whose sum is σ = 391917602. Its totient is φ = 391917600.

The previous prime is 391917599. The next prime is 391917613. The reversal of 391917601 is 106719193.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 353477601 + 38440000 = 18801^2 + 6200^2 .

It is a cyclic number.

It is not a de Polignac number, because 391917601 - 2¹ = 391917599 is a prime.

Together with 391917599, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (391917661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195958800 + 195958801.

It is an arithmetic number, because the mean of its divisors is an integer number (195958801).

Almost surely, 2^391917601 is an apocalyptic number.

It is an amenable number.

391917601 is a deficient number, since it is larger than the sum of its proper divisors (1).

391917601 is an equidigital number, since it uses as much as digits as its factorization.

391917601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10206, while the sum is 37.

The square root of 391917601 is about 19796.9088748724. The cubic root of 391917601 is about 731.8098589671.

The spelling of 391917601 in words is "three hundred ninety-one million, nine hundred seventeen thousand, six hundred one".