391097909779 has 4 divisors (see below), whose sum is σ = 391099627240. Its totient is φ = 391096192320.

The previous prime is 391097909767. The next prime is 391097909821. The reversal of 391097909779 is 977909790193.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 391097909779 - 2⁷ = 391097909651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391097909759) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 453369 + ... + 993850.

It is an arithmetic number, because the mean of its divisors is an integer number (97774906810).

Almost surely, 2^391097909779 is an apocalyptic number.

391097909779 is a deficient number, since it is larger than the sum of its proper divisors (1717461).

391097909779 is a wasteful number, since it uses less digits than its factorization.

391097909779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1717460.

The product of its (nonzero) digits is 60761421, while the sum is 70.

The spelling of 391097909779 in words is "three hundred ninety-one billion, ninety-seven million, nine hundred nine thousand, seven hundred seventy-nine".