81406285 has 8 divisors (see below), whose sum is σ = 103433976. Its totient is φ = 61294080.

The previous prime is 81406249. The next prime is 81406291. The reversal of 81406285 is 58260418.

It can be written as a sum of positive squares in 4 ways, for example, as 1643524 + 79762761 = 1282^2 + 8931^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81406285 - 2²¹ = 79309133 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81406285.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 478776 + ... + 478945.

It is an arithmetic number, because the mean of its divisors is an integer number (12929247).

Almost surely, 2^81406285 is an apocalyptic number.

81406285 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

81406285 is a deficient number, since it is larger than the sum of its proper divisors (22027691).

81406285 is a wasteful number, since it uses less digits than its factorization.

81406285 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 957743.

The product of its (nonzero) digits is 15360, while the sum is 34.

The square root of 81406285 is about 9022.5431558957. The cubic root of 81406285 is about 433.3970777363.

The spelling of 81406285 in words is "eighty-one million, four hundred six thousand, two hundred eighty-five".