840987649 has 2 divisors, whose sum is σ = 840987650. Its totient is φ = 840987648.

The previous prime is 840987547. The next prime is 840987673. The reversal of 840987649 is 946789048.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 615387249 + 225600400 = 24807^2 + 15020^2 .

It is a cyclic number.

It is not a de Polignac number, because 840987649 - 2⁹ = 840987137 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 840987649.

It is not a weakly prime, because it can be changed into another prime (840981649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420493824 + 420493825.

It is an arithmetic number, because the mean of its divisors is an integer number (420493825).

Almost surely, 2^840987649 is an apocalyptic number.

It is an amenable number.

840987649 is a deficient number, since it is larger than the sum of its proper divisors (1).

840987649 is an equidigital number, since it uses as much as digits as its factorization.

840987649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3483648, while the sum is 55.

The square root of 840987649 is about 28999.7870509423. The cubic root of 840987649 is about 943.9084469198.

The spelling of 840987649 in words is "eight hundred forty million, nine hundred eighty-seven thousand, six hundred forty-nine".