391781997403 has 2 divisors, whose sum is σ = 391781997404. Its totient is φ = 391781997402.

The previous prime is 391781997389. The next prime is 391781997461. The reversal of 391781997403 is 304799187193.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 391781997403 - 2⁹ = 391781996891 is a prime.

It is not a weakly prime, because it can be changed into another prime (391781997203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195890998701 + 195890998702.

It is an arithmetic number, because the mean of its divisors is an integer number (195890998702).

Almost surely, 2^391781997403 is an apocalyptic number.

391781997403 is a deficient number, since it is larger than the sum of its proper divisors (1).

391781997403 is an equidigital number, since it uses as much as digits as its factorization.

391781997403 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10287648, while the sum is 61.

The spelling of 391781997403 in words is "three hundred ninety-one billion, seven hundred eighty-one million, nine hundred ninety-seven thousand, four hundred three".