840200391 has 16 divisors (see below), whose sum is σ = 1252990720. Its totient is φ = 556421400.

The previous prime is 840200381. The next prime is 840200407. The reversal of 840200391 is 193002048.

It is not a de Polignac number, because 840200391 - 2⁵ = 840200359 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840200381) 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 15 ways as a sum of consecutive naturals, for example, 98965 + ... + 107118.

It is an arithmetic number, because the mean of its divisors is an integer number (78311920).

Almost surely, 2^840200391 is an apocalyptic number.

840200391 is a deficient number, since it is larger than the sum of its proper divisors (412790329).

840200391 is a wasteful number, since it uses less digits than its factorization.

840200391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206243 (or 206237 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 840200391 is about 28986.2103594106. The cubic root of 840200391 is about 943.6138205274.

The spelling of 840200391 in words is "eight hundred forty million, two hundred thousand, three hundred ninety-one".