81117405 has 12 divisors (see below), whose sum is σ = 140603580. Its totient is φ = 43262592.

The previous prime is 81117397. The next prime is 81117409. The reversal of 81117405 is 50471118.

It can be written as a sum of positive squares in 2 ways, for example, as 25674489 + 55442916 = 5067^2 + 7446^2 .

It is not a de Polignac number, because 81117405 - 2³ = 81117397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81117409) 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, 901260 + ... + 901349.

It is an arithmetic number, because the mean of its divisors is an integer number (11716965).

Almost surely, 2^81117405 is an apocalyptic number.

It is an amenable number.

81117405 is a deficient number, since it is larger than the sum of its proper divisors (59486175).

81117405 is a wasteful number, since it uses less digits than its factorization.

81117405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1802620 (or 1802617 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 27.

The square root of 81117405 is about 9006.5201382110. The cubic root of 81117405 is about 432.8838162360.

The spelling of 81117405 in words is "eighty-one million, one hundred seventeen thousand, four hundred five".