840678931 has 2 divisors, whose sum is σ = 840678932. Its totient is φ = 840678930.

The previous prime is 840678901. The next prime is 840678947. The reversal of 840678931 is 139876048.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 840678931 - 2⁵ = 840678899 is a prime.

It is a super-2 number, since 2×840678931² = 1413482130054605522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (840678901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420339465 + 420339466.

It is an arithmetic number, because the mean of its divisors is an integer number (420339466).

Almost surely, 2^840678931 is an apocalyptic number.

840678931 is a deficient number, since it is larger than the sum of its proper divisors (1).

840678931 is an equidigital number, since it uses as much as digits as its factorization.

840678931 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 290304, while the sum is 46.

The square root of 840678931 is about 28994.4637991462. The cubic root of 840678931 is about 943.7929330585.

The spelling of 840678931 in words is "eight hundred forty million, six hundred seventy-eight thousand, nine hundred thirty-one".