81140705 has 8 divisors (see below), whose sum is σ = 97468800. Its totient is φ = 64845936.

The previous prime is 81140701. The next prime is 81140713. The reversal of 81140705 is 50704118.

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

It is a cyclic number.

It is not a de Polignac number, because 81140705 - 2² = 81140701 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81140701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2615 + ... + 13004.

It is an arithmetic number, because the mean of its divisors is an integer number (12183600).

Almost surely, 2^81140705 is an apocalyptic number.

It is an amenable number.

81140705 is a deficient number, since it is larger than the sum of its proper divisors (16328095).

81140705 is a wasteful number, since it uses less digits than its factorization.

81140705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16663.

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 81140705 is about 9007.8135526886. The cubic root of 81140705 is about 432.9252591600.

The spelling of 81140705 in words is "eighty-one million, one hundred forty thousand, seven hundred five".