81018705 has 8 divisors (see below), whose sum is σ = 129629952. Its totient is φ = 43209968.

The previous prime is 81018703. The next prime is 81018731. The reversal of 81018705 is 50781018.

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 81018705 - 2¹ = 81018703 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (81018701) 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, 2700609 + ... + 2700638.

It is an arithmetic number, because the mean of its divisors is an integer number (16203744).

Almost surely, 2^81018705 is an apocalyptic number.

It is an amenable number.

81018705 is a deficient number, since it is larger than the sum of its proper divisors (48611247).

81018705 is a wasteful number, since it uses less digits than its factorization.

81018705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5401255.

The product of its (nonzero) digits is 2240, while the sum is 30.

The square root of 81018705 is about 9001.0391066810. The cubic root of 81018705 is about 432.7081738106.

The spelling of 81018705 in words is "eighty-one million, eighteen thousand, seven hundred five".