840090981 has 8 divisors (see below), whose sum is σ = 1120259520. Its totient is φ = 559991552.

The previous prime is 840090973. The next prime is 840090991. The reversal of 840090981 is 189090048.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 840090981 - 2³ = 840090973 is a prime.

It is a super-2 number, since 2×840090981² = 1411505712715084722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840090931) 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 7 ways as a sum of consecutive naturals, for example, 28165 + ... + 49733.

It is an arithmetic number, because the mean of its divisors is an integer number (140032440).

Almost surely, 2^840090981 is an apocalyptic number.

It is an amenable number.

840090981 is a deficient number, since it is larger than the sum of its proper divisors (280168539).

840090981 is a wasteful number, since it uses less digits than its factorization.

840090981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34555.

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 840090981 is about 28984.3230212472. The cubic root of 840090981 is about 943.5728599538.

The spelling of 840090981 in words is "eight hundred forty million, ninety thousand, nine hundred eighty-one".