891855557 has 2 divisors, whose sum is σ = 891855558. Its totient is φ = 891855556.

The previous prime is 891855541. The next prime is 891855631. The reversal of 891855557 is 755558198.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 489692641 + 402162916 = 22129^2 + 20054^2 .

It is a cyclic number.

It is not a de Polignac number, because 891855557 - 2⁴ = 891855541 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 891855499 and 891855508.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (891855457) 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, 445927778 + 445927779.

It is an arithmetic number, because the mean of its divisors is an integer number (445927779).

Almost surely, 2^891855557 is an apocalyptic number.

It is an amenable number.

891855557 is a deficient number, since it is larger than the sum of its proper divisors (1).

891855557 is an equidigital number, since it uses as much as digits as its factorization.

891855557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2520000, while the sum is 53.

The square root of 891855557 is about 29863.9507935571. The cubic root of 891855557 is about 962.5681946847.

The spelling of 891855557 in words is "eight hundred ninety-one million, eight hundred fifty-five thousand, five hundred fifty-seven".