19791649 has 2 divisors, whose sum is σ = 19791650. Its totient is φ = 19791648.

The previous prime is 19791637. The next prime is 19791691. The reversal of 19791649 is 94619791.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19360000 + 431649 = 4400^2 + 657^2 .

It is a cyclic number.

It is not a de Polignac number, because 19791649 - 2⁵ = 19791617 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19791599 and 19791608.

It is not a weakly prime, because it can be changed into another prime (19791049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9895824 + 9895825.

It is an arithmetic number, because the mean of its divisors is an integer number (9895825).

Almost surely, 2^19791649 is an apocalyptic number.

It is an amenable number.

19791649 is a deficient number, since it is larger than the sum of its proper divisors (1).

19791649 is an equidigital number, since it uses as much as digits as its factorization.

19791649 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 122472, while the sum is 46.

The square root of 19791649 is about 4448.7806194507. The cubic root of 19791649 is about 270.4958833964.

The spelling of 19791649 in words is "nineteen million, seven hundred ninety-one thousand, six hundred forty-nine".