840505969 has 4 divisors (see below), whose sum is σ = 842796544. Its totient is φ = 838215396.

The previous prime is 840505957. The next prime is 840505973. The reversal of 840505969 is 969505048.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-840505969 is a prime.

It is a super-2 number, since 2×840505969² = 1412900567849257922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (840505979) 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, 1144737 + ... + 1145470.

It is an arithmetic number, because the mean of its divisors is an integer number (210699136).

Almost surely, 2^840505969 is an apocalyptic number.

It is an amenable number.

840505969 is a deficient number, since it is larger than the sum of its proper divisors (2290575).

840505969 is a wasteful number, since it uses less digits than its factorization.

840505969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2290574.

The product of its (nonzero) digits is 388800, while the sum is 46.

The square root of 840505969 is about 28991.4809728651. The cubic root of 840505969 is about 943.7282030315.

The spelling of 840505969 in words is "eight hundred forty million, five hundred five thousand, nine hundred sixty-nine".