891957881 has 2 divisors, whose sum is σ = 891957882. Its totient is φ = 891957880.

The previous prime is 891957851. The next prime is 891957883. The reversal of 891957881 is 188759198.

891957881 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 531717481 + 360240400 = 23059^2 + 18980^2 .

It is a cyclic number.

It is not a de Polignac number, because 891957881 - 2¹⁴ = 891941497 is a prime.

It is a super-2 number, since 2×891957881² = 1591177722956020322, which contains 22 as substring.

Together with 891957883, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (891957883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445978940 + 445978941.

It is an arithmetic number, because the mean of its divisors is an integer number (445978941).

Almost surely, 2^891957881 is an apocalyptic number.

It is an amenable number.

891957881 is a deficient number, since it is larger than the sum of its proper divisors (1).

891957881 is an equidigital number, since it uses as much as digits as its factorization.

891957881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1451520, while the sum is 56.

The square root of 891957881 is about 29865.6639135982. The cubic root of 891957881 is about 962.6050056012.

The spelling of 891957881 in words is "eight hundred ninety-one million, nine hundred fifty-seven thousand, eight hundred eighty-one".