840132781 has 2 divisors, whose sum is σ = 840132782. Its totient is φ = 840132780.

The previous prime is 840132773. The next prime is 840132793. The reversal of 840132781 is 187231048.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 421275625 + 418857156 = 20525^2 + 20466^2 .

It is a cyclic number.

It is not a de Polignac number, because 840132781 - 2³ = 840132773 is a prime.

It is a super-2 number, since 2×840132781² = 1411646179421587922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840132721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420066390 + 420066391.

It is an arithmetic number, because the mean of its divisors is an integer number (420066391).

Almost surely, 2^840132781 is an apocalyptic number.

It is an amenable number.

840132781 is a deficient number, since it is larger than the sum of its proper divisors (1).

840132781 is an equidigital number, since it uses as much as digits as its factorization.

840132781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 840132781 is about 28985.0440917381. The cubic root of 840132781 is about 943.5885093269.

The spelling of 840132781 in words is "eight hundred forty million, one hundred thirty-two thousand, seven hundred eighty-one".