525166721 has 2 divisors, whose sum is σ = 525166722. Its totient is φ = 525166720.

The previous prime is 525166711. The next prime is 525166723. The reversal of 525166721 is 127661525.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 385572496 + 139594225 = 19636^2 + 11815^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-525166721 is a prime.

Together with 525166723, 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 (525166723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 262583360 + 262583361.

It is an arithmetic number, because the mean of its divisors is an integer number (262583361).

Almost surely, 2^525166721 is an apocalyptic number.

It is an amenable number.

525166721 is a deficient number, since it is larger than the sum of its proper divisors (1).

525166721 is an equidigital number, since it uses as much as digits as its factorization.

525166721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25200, while the sum is 35.

The square root of 525166721 is about 22916.5163364766. The cubic root of 525166721 is about 806.7997083990.

The spelling of 525166721 in words is "five hundred twenty-five million, one hundred sixty-six thousand, seven hundred twenty-one".