148191991 has 2 divisors, whose sum is σ = 148191992. Its totient is φ = 148191990.

The previous prime is 148191983. The next prime is 148192021. The reversal of 148191991 is 199191841.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 148191991 - 2³ = 148191983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (148191391) 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, 74095995 + 74095996.

It is an arithmetic number, because the mean of its divisors is an integer number (74095996).

Almost surely, 2^148191991 is an apocalyptic number.

148191991 is a deficient number, since it is larger than the sum of its proper divisors (1).

148191991 is an equidigital number, since it uses as much as digits as its factorization.

148191991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 43.

The square root of 148191991 is about 12173.4132846955. The cubic root of 148191991 is about 529.1858759830.

The spelling of 148191991 in words is "one hundred forty-eight million, one hundred ninety-one thousand, nine hundred ninety-one".