148191781 has 4 divisors (see below), whose sum is σ = 148589452. Its totient is φ = 147794112.

The previous prime is 148191779. The next prime is 148191809. The reversal of 148191781 is 187191841.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 187191841 = 313 ⋅598057.

It can be written as a sum of positive squares in 2 ways, for example, as 112550881 + 35640900 = 10609^2 + 5970^2 .

It is a cyclic number.

It is not a de Polignac number, because 148191781 - 2¹ = 148191779 is a prime.

It is a super-2 number, since 2×148191781² = 43921607911903922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (148191761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198276 + ... + 199021.

It is an arithmetic number, because the mean of its divisors is an integer number (37147363).

Almost surely, 2^148191781 is an apocalyptic number.

It is an amenable number.

148191781 is a deficient number, since it is larger than the sum of its proper divisors (397671).

148191781 is an equidigital number, since it uses as much as digits as its factorization.

148191781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 397670.

The product of its digits is 16128, while the sum is 40.

The square root of 148191781 is about 12173.4046593383. The cubic root of 148191781 is about 529.1856260166.

The spelling of 148191781 in words is "one hundred forty-eight million, one hundred ninety-one thousand, seven hundred eighty-one".