19856149 has 2 divisors, whose sum is σ = 19856150. Its totient is φ = 19856148.

The previous prime is 19856141. The next prime is 19856183. The reversal of 19856149 is 94165891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14062500 + 5793649 = 3750^2 + 2407^2 .

It is an emirp because it is prime and its reverse (94165891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19856149 - 2³ = 19856141 is a prime.

It is a super-2 number, since 2×19856149² = 788533306220402, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19856141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9928074 + 9928075.

It is an arithmetic number, because the mean of its divisors is an integer number (9928075).

Almost surely, 2^19856149 is an apocalyptic number.

It is an amenable number.

19856149 is a deficient number, since it is larger than the sum of its proper divisors (1).

19856149 is an equidigital number, since it uses as much as digits as its factorization.

19856149 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77760, while the sum is 43.

The square root of 19856149 is about 4456.0239002950. The cubic root of 19856149 is about 270.7894089766.

The spelling of 19856149 in words is "nineteen million, eight hundred fifty-six thousand, one hundred forty-nine".