85430781 has 36 divisors (see below), whose sum is σ = 132853500. Its totient is φ = 54867456.

The previous prime is 85430777. The next prime is 85430791. The reversal of 85430781 is 18703458.

It can be written as a sum of positive squares in 2 ways, for example, as 48525156 + 36905625 = 6966^2 + 6075^2 .

It is not a de Polignac number, because 85430781 - 2² = 85430777 is a prime.

It is a super-2 number, since 2×85430781² = 14596836684539922, which contains 22 as substring.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (85430711) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 190045 + ... + 190493.

It is an arithmetic number, because the mean of its divisors is an integer number (3690375).

Almost surely, 2^85430781 is an apocalyptic number.

85430781 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

85430781 is a deficient number, since it is larger than the sum of its proper divisors (47422719).

85430781 is an frugal number, since it uses more digits than its factorization.

85430781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 502 (or 481 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 85430781 is about 9242.8773117466. The cubic root of 85430781 is about 440.4244887599.

The spelling of 85430781 in words is "eighty-five million, four hundred thirty thousand, seven hundred eighty-one".