1906149991 has 2 divisors, whose sum is σ = 1906149992. Its totient is φ = 1906149990.

The previous prime is 1906149989. The next prime is 1906150003. The reversal of 1906149991 is 1999416091.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1999416091) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1906149991 - 2¹ = 1906149989 is a prime.

Together with 1906149989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1906149941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 953074995 + 953074996.

It is an arithmetic number, because the mean of its divisors is an integer number (953074996).

Almost surely, 2^1906149991 is an apocalyptic number.

1906149991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1906149991 is an equidigital number, since it uses as much as digits as its factorization.

1906149991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 157464, while the sum is 49.

The square root of 1906149991 is about 43659.4776766741. The cubic root of 1906149991 is about 1239.8972319878.

The spelling of 1906149991 in words is "one billion, nine hundred six million, one hundred forty-nine thousand, nine hundred ninety-one".