891187781123 has 2 divisors, whose sum is σ = 891187781124. Its totient is φ = 891187781122.

The previous prime is 891187781051. The next prime is 891187781207. The reversal of 891187781123 is 321187781198.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 891187781123 - 2¹⁴ = 891187764739 is a prime.

It is a super-2 number, since 2×891187781123² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (891187781623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445593890561 + 445593890562.

It is an arithmetic number, because the mean of its divisors is an integer number (445593890562).

Almost surely, 2^891187781123 is an apocalyptic number.

891187781123 is a deficient number, since it is larger than the sum of its proper divisors (1).

891187781123 is an equidigital number, since it uses as much as digits as its factorization.

891187781123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1354752, while the sum is 56.

The spelling of 891187781123 in words is "eight hundred ninety-one billion, one hundred eighty-seven million, seven hundred eighty-one thousand, one hundred twenty-three".