86845721 has 2 divisors, whose sum is σ = 86845722. Its totient is φ = 86845720.

The previous prime is 86845657. The next prime is 86845757. The reversal of 86845721 is 12754868.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 66015625 + 20830096 = 8125^2 + 4564^2 .

It is a cyclic number.

It is not a de Polignac number, because 86845721 - 2⁶ = 86845657 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (86845621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43422860 + 43422861.

It is an arithmetic number, because the mean of its divisors is an integer number (43422861).

Almost surely, 2^86845721 is an apocalyptic number.

It is an amenable number.

86845721 is a deficient number, since it is larger than the sum of its proper divisors (1).

86845721 is an equidigital number, since it uses as much as digits as its factorization.

86845721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 107520, while the sum is 41.

The square root of 86845721 is about 9319.1051609047. The cubic root of 86845721 is about 442.8426847418.

The spelling of 86845721 in words is "eighty-six million, eight hundred forty-five thousand, seven hundred twenty-one".