840505901 has 4 divisors (see below), whose sum is σ = 840614112. Its totient is φ = 840397692.

The previous prime is 840505889. The next prime is 840505903. The reversal of 840505901 is 109505048.

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 not a de Polignac number, because 840505901 - 2⁶ = 840505837 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840505903) 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, 41471 + ... + 58316.

It is an arithmetic number, because the mean of its divisors is an integer number (210153528).

Almost surely, 2^840505901 is an apocalyptic number.

It is an amenable number.

840505901 is a deficient number, since it is larger than the sum of its proper divisors (108211).

840505901 is an equidigital number, since it uses as much as digits as its factorization.

840505901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108210.

The product of its (nonzero) digits is 7200, while the sum is 32.

The square root of 840505901 is about 28991.4798001068. The cubic root of 840505901 is about 943.7281775812.

The spelling of 840505901 in words is "eight hundred forty million, five hundred five thousand, nine hundred one".