868629781 has 2 divisors, whose sum is σ = 868629782. Its totient is φ = 868629780.

The previous prime is 868629763. The next prime is 868629787. The reversal of 868629781 is 187926868.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 868186225 + 443556 = 29465^2 + 666^2 .

It is a cyclic number.

It is not a de Polignac number, because 868629781 - 2⁷ = 868629653 is a prime.

It is a super-3 number, since 3×868629781³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (868629787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 434314890 + 434314891.

It is an arithmetic number, because the mean of its divisors is an integer number (434314891).

Almost surely, 2^868629781 is an apocalyptic number.

It is an amenable number.

868629781 is a deficient number, since it is larger than the sum of its proper divisors (1).

868629781 is an equidigital number, since it uses as much as digits as its factorization.

868629781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2322432, while the sum is 55.

The square root of 868629781 is about 29472.5258673226. The cubic root of 868629781 is about 954.1388327911.

The spelling of 868629781 in words is "eight hundred sixty-eight million, six hundred twenty-nine thousand, seven hundred eighty-one".