85011871921 has 2 divisors, whose sum is σ = 85011871922. Its totient is φ = 85011871920.

The previous prime is 85011871877. The next prime is 85011871993. The reversal of 85011871921 is 12917811058.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45345573025 + 39666298896 = 212945^2 + 199164^2 .

It is a cyclic number.

It is not a de Polignac number, because 85011871921 - 2⁹ = 85011871409 is a prime.

It is not a weakly prime, because it can be changed into another prime (85011877921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42505935960 + 42505935961.

It is an arithmetic number, because the mean of its divisors is an integer number (42505935961).

Almost surely, 2^85011871921 is an apocalyptic number.

It is an amenable number.

85011871921 is a deficient number, since it is larger than the sum of its proper divisors (1).

85011871921 is an equidigital number, since it uses as much as digits as its factorization.

85011871921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40320, while the sum is 43.

The spelling of 85011871921 in words is "eighty-five billion, eleven million, eight hundred seventy-one thousand, nine hundred twenty-one".