85517061377821 has 2 divisors, whose sum is σ = 85517061377822. Its totient is φ = 85517061377820.

The previous prime is 85517061377747. The next prime is 85517061377833. The reversal of 85517061377821 is 12877316071558.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67297182552196 + 18219878825625 = 8203486^2 + 4268475^2 .

It is a cyclic number.

It is not a de Polignac number, because 85517061377821 - 2²³ = 85517052989213 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 85517061377821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85517061347821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42758530688910 + 42758530688911.

It is an arithmetic number, because the mean of its divisors is an integer number (42758530688911).

Almost surely, 2^{85517061377821} is an apocalyptic number.

It is an amenable number.

85517061377821 is a deficient number, since it is larger than the sum of its proper divisors (1).

85517061377821 is an equidigital number, since it uses as much as digits as its factorization.

85517061377821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19756800, while the sum is 61.

The spelling of 85517061377821 in words is "eighty-five trillion, five hundred seventeen billion, sixty-one million, three hundred seventy-seven thousand, eight hundred twenty-one".