1806996991 has 2 divisors, whose sum is σ = 1806996992. Its totient is φ = 1806996990.

The previous prime is 1806996979. The next prime is 1806997007. The reversal of 1806996991 is 1996996081.

It is a weak prime.

It is an emirp because it is prime and its reverse (1996996081) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1669669081 and 1809669661.

It is a cyclic number.

It is not a de Polignac number, because 1806996991 - 2²¹ = 1804899839 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1806996091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 903498495 + 903498496.

It is an arithmetic number, because the mean of its divisors is an integer number (903498496).

Almost surely, 2^1806996991 is an apocalyptic number.

1806996991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1806996991 is an equidigital number, since it uses as much as digits as its factorization.

1806996991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1889568, while the sum is 58.

The square root of 1806996991 is about 42508.7872209970. The cubic root of 1806996991 is about 1218.0145505401.

The spelling of 1806996991 in words is "one billion, eight hundred six million, nine hundred ninety-six thousand, nine hundred ninety-one".