891866089 has 2 divisors, whose sum is σ = 891866090. Its totient is φ = 891866088.

The previous prime is 891866069. The next prime is 891866111. The reversal of 891866089 is 980668198.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 791465689 + 100400400 = 28133^2 + 10020^2 .

It is a cyclic number.

It is not a de Polignac number, because 891866089 - 2²¹ = 889768937 is a prime.

It is not a weakly prime, because it can be changed into another prime (891866069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445933044 + 445933045.

It is an arithmetic number, because the mean of its divisors is an integer number (445933045).

Almost surely, 2^891866089 is an apocalyptic number.

It is an amenable number.

891866089 is a deficient number, since it is larger than the sum of its proper divisors (1).

891866089 is an equidigital number, since it uses as much as digits as its factorization.

891866089 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1492992, while the sum is 55.

The square root of 891866089 is about 29864.1271260353. The cubic root of 891866089 is about 962.5719836870.

The spelling of 891866089 in words is "eight hundred ninety-one million, eight hundred sixty-six thousand, eighty-nine".