891257489 has 2 divisors, whose sum is σ = 891257490. Its totient is φ = 891257488.

The previous prime is 891257449. The next prime is 891257509. The reversal of 891257489 is 984752198.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 635897089 + 255360400 = 25217^2 + 15980^2 .

It is a cyclic number.

It is not a de Polignac number, because 891257489 - 2⁸ = 891257233 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 891257489.

It is not a weakly prime, because it can be changed into another prime (891257449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445628744 + 445628745.

It is an arithmetic number, because the mean of its divisors is an integer number (445628745).

Almost surely, 2^891257489 is an apocalyptic number.

It is an amenable number.

891257489 is a deficient number, since it is larger than the sum of its proper divisors (1).

891257489 is an equidigital number, since it uses as much as digits as its factorization.

891257489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1451520, while the sum is 53.

The square root of 891257489 is about 29853.9359046676. The cubic root of 891257489 is about 962.3529842132.

The spelling of 891257489 in words is "eight hundred ninety-one million, two hundred fifty-seven thousand, four hundred eighty-nine".