81415305 has 12 divisors (see below), whose sum is σ = 141119940. Its totient is φ = 43421472.

The previous prime is 81415303. The next prime is 81415307. The reversal of 81415305 is 50351418.

It is an interprime number because it is at equal distance from previous prime (81415303) and next prime (81415307).

It can be written as a sum of positive squares in 2 ways, for example, as 27657081 + 53758224 = 5259^2 + 7332^2 .

It is not a de Polignac number, because 81415305 - 2¹ = 81415303 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81415303) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 904570 + ... + 904659.

It is an arithmetic number, because the mean of its divisors is an integer number (11759995).

Almost surely, 2^81415305 is an apocalyptic number.

It is an amenable number.

81415305 is a deficient number, since it is larger than the sum of its proper divisors (59704635).

81415305 is a wasteful number, since it uses less digits than its factorization.

81415305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1809240 (or 1809237 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 27.

The square root of 81415305 is about 9023.0430011166. The cubic root of 81415305 is about 433.4130842697.

The spelling of 81415305 in words is "eighty-one million, four hundred fifteen thousand, three hundred five".