856865749 has 2 divisors, whose sum is σ = 856865750. Its totient is φ = 856865748.

The previous prime is 856865741. The next prime is 856865783. The reversal of 856865749 is 947568658.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 828403524 + 28462225 = 28782^2 + 5335^2 .

It is a cyclic number.

It is not a de Polignac number, because 856865749 - 2³ = 856865741 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 856865693 and 856865702.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (856865741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 428432874 + 428432875.

It is an arithmetic number, because the mean of its divisors is an integer number (428432875).

Almost surely, 2^856865749 is an apocalyptic number.

It is an amenable number.

856865749 is a deficient number, since it is larger than the sum of its proper divisors (1).

856865749 is an equidigital number, since it uses as much as digits as its factorization.

856865749 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14515200, while the sum is 58.

The square root of 856865749 is about 29272.2692834020. The cubic root of 856865749 is about 949.8118737363.

The spelling of 856865749 in words is "eight hundred fifty-six million, eight hundred sixty-five thousand, seven hundred forty-nine".