891645497 has 2 divisors, whose sum is σ = 891645498. Its totient is φ = 891645496.

The previous prime is 891645493. The next prime is 891645523. The reversal of 891645497 is 794546198.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 648160681 + 243484816 = 25459^2 + 15604^2 .

It is a cyclic number.

It is not a de Polignac number, because 891645497 - 2² = 891645493 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (891645493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445822748 + 445822749.

It is an arithmetic number, because the mean of its divisors is an integer number (445822749).

Almost surely, 2^891645497 is an apocalyptic number.

It is an amenable number.

891645497 is a deficient number, since it is larger than the sum of its proper divisors (1).

891645497 is an equidigital number, since it uses as much as digits as its factorization.

891645497 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2177280, while the sum is 53.

The square root of 891645497 is about 29860.4336371728. The cubic root of 891645497 is about 962.4926170682.

The spelling of 891645497 in words is "eight hundred ninety-one million, six hundred forty-five thousand, four hundred ninety-seven".