891643 has 2 divisors, whose sum is σ = 891644. Its totient is φ = 891642.

The previous prime is 891629. The next prime is 891647. The reversal of 891643 is 346198.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 891643 - 2¹³ = 883451 is a prime.

It is not a weakly prime, because it can be changed into another prime (891647) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445821 + 445822.

It is an arithmetic number, because the mean of its divisors is an integer number (445822).

2⁸⁹¹⁶⁴³ is an apocalyptic number.

891643 is a deficient number, since it is larger than the sum of its proper divisors (1).

891643 is an equidigital number, since it uses as much as digits as its factorization.

891643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 31.

The square root of 891643 is about 944.2684999512. The cubic root of 891643 is about 96.2491718600.

The spelling of 891643 in words is "eight hundred ninety-one thousand, six hundred forty-three".