868041521 has 2 divisors, whose sum is σ = 868041522. Its totient is φ = 868041520.

The previous prime is 868041487. The next prime is 868041523. The reversal of 868041521 is 125140868.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 564585121 + 303456400 = 23761^2 + 17420^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-868041521 is a prime.

Together with 868041523, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (868041523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 434020760 + 434020761.

It is an arithmetic number, because the mean of its divisors is an integer number (434020761).

Almost surely, 2^868041521 is an apocalyptic number.

It is an amenable number.

868041521 is a deficient number, since it is larger than the sum of its proper divisors (1).

868041521 is an equidigital number, since it uses as much as digits as its factorization.

868041521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15360, while the sum is 35.

The square root of 868041521 is about 29462.5443741711. The cubic root of 868041521 is about 953.9233944556.

The spelling of 868041521 in words is "eight hundred sixty-eight million, forty-one thousand, five hundred twenty-one".