840885991 has 6 divisors (see below), whose sum is σ = 924279776. Its totient is φ = 764441700.

The previous prime is 840885989. The next prime is 840886009. The reversal of 840885991 is 199588048.

It is not a de Polignac number, because 840885991 - 2¹ = 840885989 is a prime.

It is a super-3 number, since 3×840885991³ (a number of 28 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840885901) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3474615 + ... + 3474856.

Almost surely, 2^840885991 is an apocalyptic number.

840885991 is a deficient number, since it is larger than the sum of its proper divisors (83393785).

840885991 is a wasteful number, since it uses less digits than its factorization.

840885991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6949493 (or 6949482 counting only the distinct ones).

The product of its (nonzero) digits is 829440, while the sum is 52.

The square root of 840885991 is about 28998.0342609633. The cubic root of 840885991 is about 943.8704123892.

The spelling of 840885991 in words is "eight hundred forty million, eight hundred eighty-five thousand, nine hundred ninety-one".