81956166 has 8 divisors (see below), whose sum is σ = 163912344. Its totient is φ = 27318720.

The previous prime is 81956159. The next prime is 81956183. The reversal of 81956166 is 66165918.

It is a happy number.

81956166 is nontrivially palindromic in base 5.

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

81956166 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6829675 + ... + 6829686.

It is an arithmetic number, because the mean of its divisors is an integer number (20489043).

Almost surely, 2^81956166 is an apocalyptic number.

81956166 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81956166 is a wasteful number, since it uses less digits than its factorization.

81956166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13659366.

The product of its digits is 77760, while the sum is 42.

The square root of 81956166 is about 9052.9644868408. The cubic root of 81956166 is about 434.3707217701.

It can be divided in two parts, 819 and 56166, that multiplied together give a palindrome (45999954).

The spelling of 81956166 in words is "eighty-one million, nine hundred fifty-six thousand, one hundred sixty-six".