840401869 has 4 divisors (see below), whose sum is σ = 846042300. Its totient is φ = 834761440.

The previous prime is 840401839. The next prime is 840401873. The reversal of 840401869 is 968104048.

840401869 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 424772100 + 415629769 = 20610^2 + 20387^2 .

It is a cyclic number.

It is not a de Polignac number, because 840401869 - 2⁹ = 840401357 is a prime.

It is a super-2 number, since 2×840401869² = 1412550602837386322, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840401839) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2819992 + ... + 2820289.

It is an arithmetic number, because the mean of its divisors is an integer number (211510575).

Almost surely, 2^840401869 is an apocalyptic number.

It is an amenable number.

840401869 is a deficient number, since it is larger than the sum of its proper divisors (5640431).

840401869 is a wasteful number, since it uses less digits than its factorization.

840401869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5640430.

The product of its (nonzero) digits is 55296, while the sum is 40.

The square root of 840401869 is about 28989.6855622823. The cubic root of 840401869 is about 943.6892399284.

The spelling of 840401869 in words is "eight hundred forty million, four hundred one thousand, eight hundred sixty-nine".