897521861 has 2 divisors, whose sum is σ = 897521862. Its totient is φ = 897521860.

The previous prime is 897521813. The next prime is 897521879. The reversal of 897521861 is 168125798.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 783160225 + 114361636 = 27985^2 + 10694^2 .

It is a cyclic number.

It is not a de Polignac number, because 897521861 - 2²⁶ = 830412997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (897521881) 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, 448760930 + 448760931.

It is an arithmetic number, because the mean of its divisors is an integer number (448760931).

Almost surely, 2^897521861 is an apocalyptic number.

It is an amenable number.

897521861 is a deficient number, since it is larger than the sum of its proper divisors (1).

897521861 is an equidigital number, since it uses as much as digits as its factorization.

897521861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 47.

The square root of 897521861 is about 29958.6692127671. The cubic root of 897521861 is about 964.6024156140.

The spelling of 897521861 in words is "eight hundred ninety-seven million, five hundred twenty-one thousand, eight hundred sixty-one".