81956011 has 4 divisors (see below), whose sum is σ = 81991800. Its totient is φ = 81920224.

The previous prime is 81955927. The next prime is 81956027. The reversal of 81956011 is 11065918.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81956011 - 2⁹ = 81955499 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81956051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14206 + ... + 19123.

It is an arithmetic number, because the mean of its divisors is an integer number (20497950).

Almost surely, 2^81956011 is an apocalyptic number.

81956011 is a deficient number, since it is larger than the sum of its proper divisors (35789).

81956011 is a wasteful number, since it uses less digits than its factorization.

81956011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35788.

The product of its (nonzero) digits is 2160, while the sum is 31.

The square root of 81956011 is about 9052.9559261050. The cubic root of 81956011 is about 434.3704479346.

The spelling of 81956011 in words is "eighty-one million, nine hundred fifty-six thousand, eleven".