81849149 has 2 divisors, whose sum is σ = 81849150. Its totient is φ = 81849148.

The previous prime is 81849091. The next prime is 81849151. The reversal of 81849149 is 94194818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62647225 + 19201924 = 7915^2 + 4382^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81849149 is a prime.

Together with 81849151, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81849199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40924574 + 40924575.

It is an arithmetic number, because the mean of its divisors is an integer number (40924575).

Almost surely, 2^81849149 is an apocalyptic number.

It is an amenable number.

81849149 is a deficient number, since it is larger than the sum of its proper divisors (1).

81849149 is an equidigital number, since it uses as much as digits as its factorization.

81849149 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82944, while the sum is 44.

The square root of 81849149 is about 9047.0519507738. The cubic root of 81849149 is about 434.1815747271.

The spelling of 81849149 in words is "eighty-one million, eight hundred forty-nine thousand, one hundred forty-nine".