81405317 has 6 divisors (see below), whose sum is σ = 94696038. Its totient is φ = 69775944.

The previous prime is 81405301. The next prime is 81405341. The reversal of 81405317 is 71350418.

It can be written as a sum of positive squares in only one way, i.e., 79405921 + 1999396 = 8911^2 + 1414^2 .

It is not a de Polignac number, because 81405317 - 2⁴ = 81405301 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 81405317.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81405347) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 830618 + ... + 830715.

It is an arithmetic number, because the mean of its divisors is an integer number (15782673).

Almost surely, 2^81405317 is an apocalyptic number.

It is an amenable number.

81405317 is a deficient number, since it is larger than the sum of its proper divisors (13290721).

81405317 is a wasteful number, since it uses less digits than its factorization.

81405317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1661347 (or 1661340 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 81405317 is about 9022.4895123242. The cubic root of 81405317 is about 433.3953598918.

The spelling of 81405317 in words is "eighty-one million, four hundred five thousand, three hundred seventeen".