81956907 has 8 divisors (see below), whose sum is σ = 121417680. Its totient is φ = 54637920.

The previous prime is 81956893. The next prime is 81956923. The reversal of 81956907 is 70965918.

81956907 is a `hidden beast` number, since 81 + 9 + 569 + 0 + 7 = 666.

It is not a de Polignac number, because 81956907 - 2¹⁶ = 81891371 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81956957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1517694 + ... + 1517747.

It is an arithmetic number, because the mean of its divisors is an integer number (15177210).

Almost surely, 2^81956907 is an apocalyptic number.

81956907 is a deficient number, since it is larger than the sum of its proper divisors (39460773).

81956907 is a wasteful number, since it uses less digits than its factorization.

81956907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3035450 (or 3035444 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 45.

The square root of 81956907 is about 9053.0054125688. The cubic root of 81956907 is about 434.3720308753.

The spelling of 81956907 in words is "eighty-one million, nine hundred fifty-six thousand, nine hundred seven".