1991065377 has 8 divisors (see below), whose sum is σ = 3034004416. Its totient is φ = 1137751632.

The previous prime is 1991065343. The next prime is 1991065379. The reversal of 1991065377 is 7735601991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-1991065377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1991065379) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47406298 + ... + 47406339.

It is an arithmetic number, because the mean of its divisors is an integer number (379250552).

Almost surely, 2^1991065377 is an apocalyptic number.

It is an amenable number.

1991065377 is a deficient number, since it is larger than the sum of its proper divisors (1042939039).

1991065377 is an equidigital number, since it uses as much as digits as its factorization.

1991065377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94812647.

The product of its (nonzero) digits is 357210, while the sum is 48.

The square root of 1991065377 is about 44621.3556158932. The cubic root of 1991065377 is about 1258.0420958883.

The spelling of 1991065377 in words is "one billion, nine hundred ninety-one million, sixty-five thousand, three hundred seventy-seven".