81907706 has 8 divisors (see below), whose sum is σ = 123372084. Its totient is φ = 40783680.

The previous prime is 81907697. The next prime is 81907741. The reversal of 81907706 is 60770918.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 79477225 + 2430481 = 8915^2 + 1559^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 81907706.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 84485 + ... + 85448.

Almost surely, 2^81907706 is an apocalyptic number.

81907706 is a deficient number, since it is larger than the sum of its proper divisors (41464378).

81907706 is a wasteful number, since it uses less digits than its factorization.

81907706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170176.

The product of its (nonzero) digits is 21168, while the sum is 38.

The square root of 81907706 is about 9050.2876197389. The cubic root of 81907706 is about 434.2850916241.

The spelling of 81907706 in words is "eighty-one million, nine hundred seven thousand, seven hundred six".