85078921 has 2 divisors, whose sum is σ = 85078922. Its totient is φ = 85078920.

The previous prime is 85078907. The next prime is 85078937. The reversal of 85078921 is 12987058.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66243321 + 18835600 = 8139^2 + 4340^2 .

It is a cyclic number.

It is not a de Polignac number, because 85078921 - 2¹³ = 85070729 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (85078121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42539460 + 42539461.

It is an arithmetic number, because the mean of its divisors is an integer number (42539461).

Almost surely, 2^85078921 is an apocalyptic number.

It is an amenable number.

85078921 is a deficient number, since it is larger than the sum of its proper divisors (1).

85078921 is an equidigital number, since it uses as much as digits as its factorization.

85078921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 85078921 is about 9223.8235564217. The cubic root of 85078921 is about 439.8190044138.

The spelling of 85078921 in words is "eighty-five million, seventy-eight thousand, nine hundred twenty-one".