81312706 has 8 divisors (see below), whose sum is σ = 124270524. Its totient is φ = 39889200.

The previous prime is 81312703. The next prime is 81312709. The reversal of 81312706 is 60721318.

It is an interprime number because it is at equal distance from previous prime (81312703) and next prime (81312709).

It can be written as a sum of positive squares in 2 ways, for example, as 69472225 + 11840481 = 8335^2 + 3441^2 .

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

It is a super-2 number, since 2×81312706² = 13223512314084872, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81312701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 383445 + ... + 383656.

Almost surely, 2^81312706 is an apocalyptic number.

81312706 is a deficient number, since it is larger than the sum of its proper divisors (42957818).

81312706 is a wasteful number, since it uses less digits than its factorization.

81312706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 767156.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 81312706 is about 9017.3558208601. The cubic root of 81312706 is about 433.2309463558.

The spelling of 81312706 in words is "eighty-one million, three hundred twelve thousand, seven hundred six".