85717421 has 2 divisors, whose sum is σ = 85717422. Its totient is φ = 85717420.

The previous prime is 85717369. The next prime is 85717427. The reversal of 85717421 is 12471758.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75864100 + 9853321 = 8710^2 + 3139^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-85717421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (85717427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42858710 + 42858711.

It is an arithmetic number, because the mean of its divisors is an integer number (42858711).

Almost surely, 2^85717421 is an apocalyptic number.

It is an amenable number.

85717421 is a deficient number, since it is larger than the sum of its proper divisors (1).

85717421 is an equidigital number, since it uses as much as digits as its factorization.

85717421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15680, while the sum is 35.

The square root of 85717421 is about 9258.3703209582. The cubic root of 85717421 is about 440.9165141744.

The spelling of 85717421 in words is "eighty-five million, seven hundred seventeen thousand, four hundred twenty-one".