897731921 has 2 divisors, whose sum is σ = 897731922. Its totient is φ = 897731920.

The previous prime is 897731899. The next prime is 897731951. The reversal of 897731921 is 129137798.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 897601600 + 130321 = 29960^2 + 361^2 .

It is a cyclic number.

It is not a de Polignac number, because 897731921 - 2¹⁸ = 897469777 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (897731951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 448865960 + 448865961.

It is an arithmetic number, because the mean of its divisors is an integer number (448865961).

Almost surely, 2^897731921 is an apocalyptic number.

It is an amenable number.

897731921 is a deficient number, since it is larger than the sum of its proper divisors (1).

897731921 is an equidigital number, since it uses as much as digits as its factorization.

897731921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 190512, while the sum is 47.

The square root of 897731921 is about 29962.1748376182. The cubic root of 897731921 is about 964.6776630208.

The spelling of 897731921 in words is "eight hundred ninety-seven million, seven hundred thirty-one thousand, nine hundred twenty-one".