85821511 has 2 divisors, whose sum is σ = 85821512. Its totient is φ = 85821510.

The previous prime is 85821497. The next prime is 85821517. The reversal of 85821511 is 11512858.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 85821511 - 2²¹ = 83724359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85821517) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42910755 + 42910756.

It is an arithmetic number, because the mean of its divisors is an integer number (42910756).

Almost surely, 2^85821511 is an apocalyptic number.

85821511 is a deficient number, since it is larger than the sum of its proper divisors (1).

85821511 is an equidigital number, since it uses as much as digits as its factorization.

85821511 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3200, while the sum is 31.

The square root of 85821511 is about 9263.9900151069. The cubic root of 85821511 is about 441.0949160075.

The spelling of 85821511 in words is "eighty-five million, eight hundred twenty-one thousand, five hundred eleven".